Answer:
E. Energy
Explanation:
Electron volt is a unit of energy commonly used in various branches of physics.
It is defined as the energy gained by an electron when the electrical potential of the electron increases by one volt.
The electron volt = 1.602 × 10^−12 erg, or 1.602 × 10^−19 joule
Answer:
The electron-volt is a unit of A. charge. B. electric potential. C. electric field. D. electric force. E. energy.
The answer is option E (energy)
Explanation:
There are many forms of energy which are divided into Potential Energy, Kinetic energy and the major energy sources are nonrenewable and renewable sources. Energy makes change; it does things for us. Since energy is a fundamental physical quantity, it is a property of matter that can be converted into work, heat or radiation. Energy can be converted from one form to another, but it cannot be created, nor can it be destroyed.
Energy conversion is essential for energy utilization. Energy can be measured in many different units which includes joules, calories, electron-volts, kilowatt-hours, and so many more.
The electron-volt is a unit used to measure the energy of subatomic particles. The electron-volt, symbol eV, can be defined as the amount of energy gained by the charge of a single electron (a charged particle carrying unit electronic charge) moved across an electric potential difference of one volt. One electron-volt, eV is equal to 1.602176634×10−19 J. Where J is in joules.
A good-quality measuring tape can be off by 0.42 cm over a distance of 28 m. What is its percent uncertainty? (Express your answer to the correct number of significant figures and proper units.)
Answer:
0.015%
Explanation:
Data provided in the question:
Length by which the measuring tape can be off, δL = 0.42 cm
Total measured length for which Error of δL is observed, L = 28 m
Now,
we know,
1 m = 100 cm
Thus,
28 m = 28 × 100 = 2800 cm
Percent uncertainty = [δL ÷ L] × 100%
= [0.42 ÷ 2800] × 100%
= 0.015%
Reflected light from a thin film of oil gives constructive interference for light with a wavelength inside the film of λfilm. By how much would the film thickness need to be increased to give destructive interference?
A. 2λfilm
B. λfilm
C. λfilm/2
D. λfilm/4
The film thickness needs to be increased by C. λfilm/2 to achieve destructive interference.
Explanation:When light reflects off a thin film, it can undergo constructive or destructive interference depending on the thickness of the film and the wavelength of the light. For constructive interference, the path difference between the reflected rays should be an integer multiple of the wavelength, while for destructive interference, the path difference should be an odd multiple of half the wavelength.
Interference in thin films is a phenomenon where light waves reflect off both the top and bottom surfaces of a thin film, leading to constructive or destructive interference patterns, creating colors. Therefore, to achieve destructive interference, the film thickness needs to be increased by λfilm/2. Thus, the correct answer is option C.
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To switch from constructive to destructive interference, the film thickness must be increased by λ[tex]_f_i_l_m[/tex]/2.
In thin film interference, the thickness of the film and the wavelength of light are crucial in determining whether the interference is constructive or destructive. Constructive interference happens when the path length difference for the two reflected rays is an integral multiple of the wavelength inside the film (i.e., 2t = nλ[tex]_f_i_l_m[/tex], where n is an integer). Conversely, destructive interference occurs when this path length difference is a half-integral multiple of the wavelength (i.e., 2t = (2n + 1)λ[tex]_f_i_l_m[/tex] / 2).
Given that the film currently gives constructive interference for a wavelength of λ[tex]_f_i_l_m[/tex], the path length difference is an integral multiple of λ[tex]_f_i_l_m[/tex]. To switch to destructive interference, the thickness must be increased so the total path length difference becomes a half-integral multiple of λ[tex]_f_i_l_m[/tex]. This increase should be λ[tex]_f_i_l_m[/tex]/2.
The film thickness would need to be increased by λ[tex]_f_i_l_m[/tex]/2 to give destructive interference.
The normal boiling point of cyclohexane is 81.0 oC. What is the vapor pressure of cyclohexane at 81.0 oC?
Answer:
The vapor pressure of cyclohexane at 81.0°C is 101325 Pa.
Explanation:
Given that,
Boiling point = 81.0°C
Atmospheric pressure :
Atmospheric pressure is the force per unit area exerted by the weight of the atmosphere.
The value of atmospheric pressure is
[tex]P=101325\ Pa[/tex]
Vapor pressure :
Vapor pressure is equal to the atmospheric pressure.
Hence, The vapor pressure of cyclohexane at 81.0°C is 101325 Pa.
A 35.0-cm-diameter circular loop is rotated in a uniform electric field until the position of maximum electric flux is found. The flux in this position is measured to be 5.42 105 N · m2/C. What is the magnitude of the electric field? MN/C
To solve this problem we will apply the concept of Electric Flow, which is understood as the product between the Area and the electric field. For the data defined by the area, we will use the geometric measurement of the area in a circle (By the characteristics of the object) This area will be equivalent to,
[tex]\phi = 35 cm[/tex]
[tex]r = 17.5 cm = 0.175 m[/tex]
[tex]A = \pi r^2 = \pi (0.175)^2 = 0.09621m^2[/tex]
Applying the concept of electric flow we have to
[tex]\Phi = EA[/tex]
Replacing,
[tex]5.42*10^5N \cdot m^2/C = E (0.09621m^2)[/tex]
[tex]E = 5.6335*10^6N/C[/tex]
Therefore the magnitude of the electric field is [tex]5.6335*10^6N/C[/tex]
A 5.00 liter balloon of gas at 25°C is cooled to 0°C. What is the new volume (liters) of the balloon?
Answer:
4.58 L.
Explanation:
Given that
V₁ = 5 L
T₁ = 25°C = 273 + 25 = 298 K
T₂ = 0°C = 273 K
The final volume = V₂
We know that ,the ideal gas equation
If the pressure of the gas is constant ,then we can say that
[tex]\dfrac{V_2}{V_1}=\dfrac{T_2}{T_1}[/tex]
Now by putting the values in the above equation we get
[tex]V_2=V_1\times \dfrac{T_2}{T_1}\\V_2=5\times \dfrac{273}{298}\\V_2=4.58\ L\\[/tex]
The final volume of the balloon will be 4.58 L.
A 220 g , 23-cm-diameter plastic disk is spun on an axle through its center by an electric motor.What torque must the motor supply to take the disk from 0 to 1800 rpm in 4.6 s ?
The torque required by the motor to spin a 220g, 23-cm-diameter plastic disk from 0 to 1800 rpm in 4.6 seconds, without considering the external forces, is 0.431 Nm.
Explanation:In solving the question,
Torque
is our primary interest. We first need to convert rpm to rad/s since Torque calculations require SI units. The conversion can be done by the formula ω = 2π (frequency), and frequency is simply rpm/60. Hence, 1800 rpm is equivalent to 188.50 rad/s. Now, we use the Kinematics equation ω = ω
0
+ αt to calculate angular acceleration (α), where ω
0
is the initial angular velocity, and it is 0 rad/s in this case as the disk starts from rest, ω is the final angular velocity and is 188.50 rad/s, while t is the time of 4.6 seconds. Solving this gives us α=41 rad/s
2
. The Torque can now be calculated using τ=Iα where I (moment of inertia for a disk) = 0.5*m*r
2
. Substituting the values of m, r and α gives a Torque value of 0.431 Nm.
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An electron moving in the y direction at right angles to a magnetic field experiences a magnetic force in the x direction. The direction of the magnetic field is in the_______.
A. x direction
B. x direction
C. y direction
D. z direction
E. z direction
Answer:
The direction of the magnetic field is in the z-direction
Explanation:
Applying right hand rule, which states that when the thumb, index finger and the middle finger are held mutually at right angle to each other, with the index finger pointing in the direction of the moving charge (y- direction), the thumb pointing in the direction of the magnetic force (x-direction) pushing on the moving charge and then the middle finger pointing in the direction of the magnetic field (z-direction).
z direction.
Explanation:Using John Ambrose Fleming's right hand rule which asks to position the middle finger, the thumb and the index finger as follows;
| thumb
|
|
index |
/
/
/
/
middle
With this arrangement shown above, if you point your index finger in the direction in which the charge is moving, and then the middle finger in the direction of the magnetic field, then your thumb will point in the direction of the magnetic force.
For example;
If a charge is moving in the x direction, and the magnetic force is moving in the y direction, then the above figure is rotated to make sure that the index finger is pointing in the direction of the moving charge so as to get the direction of the magnetic field as follows;
y| thumb (magnetic force)
|
(direction of charge) |
index x |
/
/
/
/ z
middle (direction of field)
Therefore, the magnetic field is in the z direction.
Now to the question, if the charge(electron) is moving in the y direction at right angles to a magnetic field and it experiences a magnetic field in the x direction, the diagram above can be rotated to depict this situation as follows;
y| index (direction of charge)
|
|
| x
/ thumb (direction of force)
/
/
/ z
middle (direction of field)
Therefore the magnetic field will move in the z direction.
Note:
i. For every rotation of right-hand, the index finger must always point in the direction of the charge.
ii. Since the question does not specify which direction the electron is moving in (whether positive or negative), the direction of the magnetic field (whether positive or negative) might not be determined either. But in either case, the field will move in the z direction.
A baseball was hit and reached its maximum height in 3.00s. Find (a) its initial velocity; (b) the height it reaches.[29.4 m/s; 44.1m]
Answer:
u= 29.43 m/s
h=44.14 m
Explanation:
Given that
t= 3 s
We know that acceleration due to gravity ,g = 9.81 m/s² (Downward)
Initial velocity = u
Final velocity ,v= 0 (At maximum height)
We know v = u +a t
v=final velocity
u=initial velocity
a=Acceleration
Now by putting the values in the above equation
0 = u - 9.81 x 3
u= 29.43 m/s
The maximum height h is given as
v² = u ² - 2 g h
0² = 29.43 ² - 2 x 9.81 x h
[tex]h=\dfrac{29.43^2}{2\times 9.81}\ m[/tex]
h=44.14 m
A rock is thrown at an angle of 60∘ to the ground. If the rock lands 25m away, what was the initial speed of the rock? (Assume air resistance is negligible. Your answer should contain the gravitational constant ????.)
Answer:
[tex]v_0 = 16.82\ m/s[/tex]
Explanation:
given,
angle at which rock is thrown = 60°
rock lands at distance,d = 25 m
initial speed of rock, = ?
In horizontal direction
distance = speed x time
d = v₀ cos 60° t
25 = v₀ cos 60° t............(1)
now,
in vertical direction
displacement in vertical direction is zero
using equation of motion
[tex]s = ut +\dfrac{1}{2}gt^2[/tex]
[tex]0 =v_0 sin 60^0 t - 4.9 t^2[/tex]
[tex]v_o sin 60^0 = 4.9 t[/tex]
[tex]t = \dfrac{v_0 sin 60^0}{4.9}[/tex]
putting the value of t in equation (1)
[tex]25 = v_0 cos 60^0\times \dfrac{v_0 sin 60^0}{4.9}[/tex]
[tex]25 =\dfrac{v_0^2cos 60^0 sin 60^0}{4.9}[/tex]v
[tex]v_0^2 = 282.90[/tex]
[tex]v_0 = 16.82\ m/s[/tex]
Hence, the initial speed of the rock is equal to 16.82 m/s
The total distance treaveled by a car moving in a straight line is as follows: After the first 7.0 minutes it has gone a total of 2.0 miles. After 14.0 minutes it has traveled a total of 4.5 miles. Finally at 21.0 minutes it has traveled a total of 6.0 miles. Find the average speed at: Time
Answer:
Average speed of the car will be 27.582 km/hr
Explanation:
We have given that in first 5 minutes distance traveled by car is 2 miles
After 14 minutes it has travel 4.5 miles
And finally after 21 minutes distance traveled by car is 6 miles
So total time of traveling t = 21 minutes
As we know that 1 hour = 60 minutes
So 21 minutes [tex]=\frac{21}{60}=0.35hour[/tex]
Total distance traveled = 6 miles
As 1 miles = 1.609 km
So 6 miles [tex]=6\times 1.609=9.654km[/tex]
Average speed is equal to the ratio of total distance and total time
So average speed [tex]v=\frac{9.654}{0.35}=27.582km/hr[/tex]
An airplane in a holding pattern flies at constant altitude along a circular path of radius 3.38 km. If the airplane rounds half the circle in 156 s, determine the following. HINT (a) Determine the magnitude of the airplane's displacement during the given time (in m). m (b) Determine the magnitude of the airplane's average velocity during the given time (in m/s). m/s (c) What is the airplane's average speed during the same time interval (in m/s)
The displacement of the airplane is 6760 meters, its average velocity is 43.33 m/s, and its average speed is 135.08 m/s.
Explanation:To solve this problem, we need to apply the principles of physics in kinematics and circular motion. First of all, let's understand that displacement is the shortest distance the airplane covered, which is the diameter of the circle. We multiply the radius by 2 (2*3.38 km) and convert it to meters to give 6760 meters for part (a).
Next, for average velocity, which is displacement over time, we divide 6760 m by 156 s, yielding approximately 43.33 m/s for part (b).
Lastly, for average speed, we need to consider the total distance travelled. In half a circle, this is pi times the diameter. Therefore, the average speed is (3.14 * 6760 m) / 156 = 135.08 m/s for part (c).
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The magnitude of the airplane's displacement is 6760 m. The magnitude of the average velocity is 43.33 m/s, and the average speed is 67.97 m/s.
Let's break down the problem step-by-step to find the required values.
(a) Magnitude of the Airplane's Displacement:
The airplane flies half of the circle, which means the path is a semicircle. The displacement is the straight-line distance between the start and end points of this path, which is the diameter of the circle.
Radius of the circle, [tex]r = 3.38 km = 3380 m[/tex]
Diameter, [tex]d = 2 * r = 2 * 3380 m = 6760 m[/tex]
Therefore, the magnitude of the displacement is 6760 m.
(b) Magnitude of the Average Velocity:
Average velocity is the displacement divided by the time.
Displacement = 6760 m
Time, [tex]t = 156 s[/tex]
Average velocity, [tex]v_{avg} = Displacement / Time = 6760 m / 156 s = 43.33 m/s[/tex]
Therefore, the magnitude of the average velocity is 43.33 m/s.
(c) Airplane's Average Speed:
The average speed is the total distance traveled along the path divided by the time.
The distance traveled in half a circle is the circumference of the semicircle.
[tex]Distance = (\pi * Diameter) / 2 = (\pi * 6760 m) / 2 = 10602.91 m[/tex]
[tex]Average speed = Distance / Time = 10602.91 m / 156 s = 67.97 m/s[/tex]
Therefore, the airplane's average speed is 67.97 m/s.
A charge +1.9 μC is placed at the center of the hollow spherical conductor with the inner radius 3.8 cm and outer radius 5.6 cm. Suppose the conductor initially has a net charge of +3.8 μC instead of being neutral. What is the total charge (a) on the interior and (b) on the exterior surface?
To solve this problem we will apply the concepts related to load balancing. We will begin by defining what charges are acting inside and which charges are placed outside.
PART A)
The charge of the conducting shell is distributed only on its external surface. The point charge induces a negative charge on the inner surface of the conducting shell:
[tex]Q_{int}=-Q1=-1.9*10^{-6} C[/tex]. This is the total charge on the inner surface of the conducting shell.
PART B)
The positive charge (of the same value) on the external surface of the conducting shell is:
[tex]Q_{ext}=+Q_1=1.9*10^{-6} C[/tex]
The driver's net load is distributed through its outer surface. When inducing the new load, the total external load will be given by,
[tex]Q_{ext, Total}=Q_2+Q_{ext}[/tex]
[tex]Q_{ext, Total}=1.9+3.8[/tex]
[tex]Q_{ext, Total}=5.7 \mu C[/tex]
(a) The total charge on the interior of the spherical conductor is -1.9 μC.
(b) The total exterior charge of the spherical conductor is 5.7 μC.
The given parameters;
charge at the center of the hollow sphere, q = 1.9 μC inner radius of the spherical conductor, r₁ = 3.8 cmouter radius of the spherical conductor, r₂ = 5.6 cmThe total charge on the interior is calculated as follows;
[tex]Q_{int} = - 1.9 \ \mu C[/tex]
The total exterior charge is calculated as follows;
[tex]Q_{tot . \ ext} = Q + Q_2\\\\Q_{tot . \ ext} = 1.9 \ \mu C \ + \ 3.8 \ \mu C\\\\Q_{tot . \ ext} = 5.7 \ \mu C[/tex]
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You are walking down a straight path in a park and notice there is another person walking some distance ahead of you. The distance between the two of you remains the same, so you deduce that you are walking at the same speed of 1.09 m/s . Suddenly, you notice a wallet on the ground. You pick it up and realize it belongs to the person in front of you. To catch up, you start running at a speed of 2.85 m/s . It takes you 14.5 s to catch up and deliver the lost wallet. How far ahead of you was this person when you started running?
Answer:
25.52 m
Explanation:
Relative speed between the person and I would be the difference of our speeds
[tex]v_r=2.85-1.09=1.76\ m/s[/tex]
Time taken by me to walk up to the person = 14.5 s
Distance is given by
[tex]Distance=Speed\times Time\\\Rightarrow s=vt\\\Rightarrow s=1.76\times 14.5\\\Rightarrow s=25.52\ m[/tex]
The person was 25.52 m ahead of me when I started running
A 0.800kg block is attached to a spring with spring constant 16.0N/m . While the block is sitting at rest, a student hits it with a hammer and almost instantaneously gives it a speed of 34.0cm/s . What areA)The amplitude of the subsequent oscillations?B)The block's speed at the point where x= 0.250 A?
Answer:
(a) Amplitude=0.0760 m
(b) Speed=0.337 m/s
Explanation:
(a) For amplitude
We can use the mentioned description of the motion and the energy conservation principle to find amplitude of oscillatory motion
[tex]k_{i}+U_{i}=K_{f}+U_{f}\\ (1/2)mv^{2}+0=0+(1/2)kA^{2}\\ A^{2}=\frac{mv^{2}}{k} \\A=\sqrt{\frac{mv^{2}}{k}}\\ A=\sqrt{\frac{m}{k} }v\\ A=\sqrt{\frac{(0.800kg)}{16N/m} }(0.34m/s)\\A=0.0760m[/tex]
(b) For Speed
Again we can use the mentioned description of the motion and the energy conservation principle to find amplitude of oscillatory motion
[tex]k_{i}+U_{i}=K_{f}+U_{f}\\ (1/2)m(v_{i})^{2}+0=(1/2)m(v_{f} )^{2}+(1/2)k(A/2)^{2}\\ (1/2)m(v_{i})^{2}=(1/2)m(v_{f} )^{2}+(1/2)k(A/2)^{2}\\(1/2)m(v_{i})^{2}-(1/2)k(A/2)^{2}=(1/2)m(v_{f} )^{2}\\(1/2)[m(v_{i})^{2}-k(A/2)^{2}]=(1/2)m(v_{f} )^{2}\\(v_{f} )^{2}=1/m[m(v_{i})^{2}-k(A/2)^{2}]\\As\\x=0.250A\\(v_{f} )^{2}=(1/0.800kg)[0.800kg(0.34m/s)^{2}-(16N/m)(0.250(0.07602m)/2)^{2}\\(v_{f} )^{2}=0.1138\\ v_{f}=\sqrt{0.1138}\\ v_{f}=0.337m/s[/tex]
Final answer:
The amplitude and speed of the block at a specified position in SHM can be determined by using conservation of energy, equating the initial kinetic energy to the maximum potential energy at the amplitude, and calculating the speed via energy values at a given displacement from equilibrium.
Explanation:
Let's break down the problem step by step:
1. Amplitude of Subsequent Oscillations (A):
- When the block is hit with the hammer, it acquires an initial velocity of [tex]\(34.0 \, \text{cm/s}\)[/tex], which we'll convert to meters per second: [tex]\(v = 34.0 \, \text{cm/s} = 0.34 \, \text{m/s}\)[/tex].
- The mechanical energy of the system (block + spring) is conserved. At the maximum extension (amplitude) of the oscillation, the kinetic energy is zero.
- Therefore, the total mechanical energy at the maximum extension is equal to the potential energy stored in the spring:
[tex]\[ E = U = \frac{1}{2} k A^2 \][/tex]
- We can express the kinetic energy at the initial point as:
[tex]\[ K = \frac{1}{2} m v^2 \][/tex]
- Since the total mechanical energy is conserved, we have:
\[ E = K + U \]
[tex]\[ \frac{1}{2} k A^2 = \frac{1}{2} m v^2 \][/tex]
- Solving for the amplitude \(A\):
[tex]\[ A = \sqrt{\frac{m v^2}{k}} \][/tex]
Substituting the given values:
[tex]\[ A = \sqrt{\frac{0.800 \, \text{kg} \cdot (0.34 \, \text{m/s})^2}{16.0 \, \text{N/m}}} \][/tex]
Calculating:
[tex]\[ A \approx 0.34 \, \text{m} \][/tex]
Therefore, the amplitude of the subsequent oscillations is approximately 0.34 meters.
2. Block's Speed at [tex]\(x = 0.250A\)[/tex]:
- At any position \(x\), the mechanical energy \(E\) of the system is given by:
[tex]\[ E = \frac{1}{2} k x^2 + \frac{1}{2} m v^2 \][/tex]
- At the maximum extension (amplitude), the kinetic energy is zero, so:
[tex]\[ E = U(x = A) = \frac{1}{2} k A^2 \][/tex]
- We can find the speed of the block at any position \(x\) using the amplitude \(A\):
[tex]\[ v = \sqrt{\frac{k}{m} (A^2 - x^2)} \][/tex]
Substituting the given value [tex]\(x = 0.250A\)[/tex]:
[tex]\[ v = \sqrt{\frac{16.0 \, \text{N/m}}{0.800 \, \text{kg}} \left(0.34^2 - (0.250 \cdot 0.34)^2\right)} \][/tex]
Calculating:
[tex]\[ v \approx 0.24 \, \text{m/s} \][/tex]
Therefore, the block's speed at the point where [tex]\(x = 0.250A\)[/tex] is approximately 0.24 meters per second
A uniform, solid, 2000.0 kgkg sphere has a radius of 5.00 mm. Find the gravitational force this sphere exerts on a 2.10 kgkg point mass placed at the following distances from the center of the sphere: (a) 5.04 mm , and (b) 2.70 mm .
Answer:
[tex]0.0110284391534\ N[/tex]
[tex]0.0653784219002\ N[/tex]
Explanation:
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
[tex]m_1[/tex] = Mass of sphere = 2000 kg
[tex]m_2[/tex] = Mass of other sphere = 2.1 kg
r = Distance between spheres
Force of gravity is given by
[tex]F=\dfrac{Gm_1m_2}{r^2}\\\Rightarrow F=\dfrac{6.67\times 10^{-11}\times 2000\times 2.1}{(5.04\times 10^{-3})^2}\\\Rightarrow F=0.0110284391534\ N[/tex]
The gravitational force is [tex]0.0110284391534\ N[/tex]
[tex]F=\dfrac{Gm_1m_2}{r^2}\\\Rightarrow F=\dfrac{6.67\times 10^{-11}\times 2000\times 2.1}{(2.07\times 10^{-3})^2}\\\Rightarrow F=0.0653784219002\ N[/tex]
The gravitational force is [tex]0.0653784219002\ N[/tex]
One end of a string 5.02 m long is moved up and down with simple harmonic motion at a frequency of 61 Hz . The waves reach the other end of the string in 0.5 s. Find the wavelength of the waves on the string. Answer in units of cm
Answer:
Explanation:
One end of a string 5.02 m long is moved up and dowBDBBn with simple harmonic motion at a frequency of 61 Hz . The waves reach the other end of the string in 0.5 s. Find the wavelength of the waves on the string. Answer in units of cm
The wavelength of the waves on the string is calculated using the wave speed (found by distance/time) and the frequency. After performing the calculations, the wavelength is determined to be 16.46 cm.
To calculate the wavelength of the waves on the string, we can use the wave speed and the frequency. The speed of a wave ( is given by the formula speed = distance / time. Here, the distance is the length of the string, and the time is how long it takes for waves to reach the other end.
The speed of the wave is therefore 5.02 m / 0.5 s = 10.04 m/s. The frequency of the wave is given as 61 Hz. The wavelength ( can be found using the equation v = f, where v is the wave speed, f is the frequency, and is the wavelength.
By rearranging the equation to solve for the wavelength, we get
= v / f. Substituting the given values, we find
= 10.04 m/s / 61 Hz
= 0.1646 m. To convert the wavelength into centimeters, we multiply by 100, which gives us a wavelength of 16.46 cm.
In flow over cylinders, why does the drag coefficient suddenly drop when the flow becomes turbulent?
For a body with an aerodynamic profile to reach a low resistance coefficient, the boundary layer around the body must remain attached to its surface for as long as possible. In this way, the wake produced becomes narrow. A high shape resistance results in a wide wake. In this type of bodies, if there is turbulence, the drag coefficient increases because the pressure drag appears.
However, in the case of cylinders, it happens that the separation point of the boundary layer will move towards to the rear of the body, which will reduce the size of the wake and there will reduce the magnitude of the pressure drag.
In fluid dynamics, the sudden drop in drag coefficient when flow over a cylinder becomes turbulent is due to the shift from laminar to turbulent flow. As turbulence increases and 'energizes' the slower boundary layer of fluid on the cylinder, the overall drag is reduced and the drag coefficient decreases.
Explanation:In flow over cylinders, the sudden drop in the drag coefficient when the flow becomes turbulent can be attributed to the shift from laminar to turbulent flow itself. As the speed or Reynolds number (N'R) increases, the type of flow changes, and so does the behavior of the viscous drag exerted on the moving object.
In laminar flow, layers flow without mixing and the viscous drag is proportional to speed. As the Reynolds number enters the turbulent range, the drag begins to increase according to a different rule, becoming proportional to speed squared. This turbulent flow introduces eddies and swirls that mix fluid layers.
However, beyond a point in the turbulent flow regime, the drag coefficient starts to decrease. This is because the turbulence begins to 'energize' the generally slower, boundary layer of fluid that clings to the surface of the cylinder, which reduces the overall strength of the drag created by the flow. Moreover, these energized layers of fluid effectively 'smooth out' the obstructive effect of the cylinder, leading to a sudden decrease in the drag coefficient.
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An infinitely long line of charge has linear charge density 6.00×10−12 C/m . A proton (mass 1.67×10−27 kg,charge +1.60×10−19 C) is 12.0 cm from the line and moving directly toward the line at 4.10×103 m/s .
a)Calculate the proton's initial kinetic energy. Express your answer with the appropriate units.
b)How close does the proton get to the line of charge? Express your answer with the appropriate units.
Final Answer:
a) The proton's initial kinetic energy is [tex]\(8.66 \times 10^{-16}\)[/tex]J.
b) The proton gets as close as 6.00 cm to the line of charge.
Explanation:
a) In part (a), the initial kinetic energy of the proton can be calculated using the formula [tex]\(KE = \frac{1}{2}mv^2\),[/tex]where [tex]\(m\)[/tex] is the mass of the proton and [tex]\(v\)[/tex] is its velocity.
Substituting the given values, we get [tex]\(KE = \frac{1}{2}(1.67 \times 10^{-27}\, \text{kg})(4.10 \times 10^3\, \text{m/s})^2\),[/tex] resulting in [tex]\(8.66 \times 10^{-16}\) J.[/tex]
b) In part (b), the proton's closest approach can be determined using the formula for electric potential energy [tex](\(PE\))[/tex] and kinetic energy [tex](\(KE\))[/tex] when the proton is momentarily at rest.
At the closest point, all the initial kinetic energy is converted to electric potential energy, so The electric potential energy is given by [tex]\(PE = \frac{k \cdot q_1 \cdot q_2}{r}\),[/tex] where [tex]\(k\)[/tex] is Coulomb's constant, [tex]\(q_1\) and \(q_2\)[/tex] are the charges, and [tex]\(r\)[/tex] is the separation distance. Substituting the known values, [tex]\(q_1 = 1.60 \times 10^{-19}\, \text{C}\), \(q_2\)[/tex] is the charge density multiplied by the length per unit length, and [tex]\(r\)[/tex] is the distance, we can solve for [tex]\(r\),[/tex] resulting in [tex]\(6.00\, \text{cm}\).[/tex]
Final answer:
The initial kinetic energy of the proton is calculated using the formula KE = 1/2 * m * v^2, yielding 1.40x10^-20 J. The question regarding how close the proton gets to the line of charge cannot be completely answered without additional details, such as the electric field strength around the linear charge.
Explanation:
The question involves calculations relating to a proton's motion in the electric field created by a linear charge. This falls under the subject of physics and includes principles of electromagnetism and kinematics, typically taught in college-level physics courses.
a) Calculate the proton's initial kinetic energy
The kinetic energy (KE) of an object moving with velocity v is given by the equation KE = 1/2 * m * v^2, where m is the mass of the object. For a proton with mass 1.67x10^-27 kg moving at 4.10x10^3 m/s, its initial kinetic energy is:
KE = 1/2 * (1.67x10^-27 kg) * (4.10x10^3 m/s)^2 = 1.40x10^-20 J.
b) How close does the proton get to the line of charge?
This part requires the concept of energy conservation and electrostatic force. However, without specifying the potential energy due to the proton's interaction with the linear charge, the question is incomplete. Usually, one would calculate the potential energy at the closest approach and set it equal to the original kinetic energy to solve for the distance. The issue requires more information, such as the electric field strength around the line of charge, to proceed with the calculation.
You have a neutral balloon. What is its charge after 12000 electrons have been removed from it? The elemental charge is 1.6 × 10−19 C. Answer in units of µC.
Final answer:
Upon removing 12000 electrons from a neutral balloon, it will acquire a positive charge of 1.92 microcoulombs (1.92 µC). This is calculated by multiplying the number of electrons by the elemental charge and converting to the appropriate unit.
Explanation:
When 12000 electrons are removed from a neutral balloon, it obtains a positive charge because electrons carry a negative charge. To determine the charge the balloon now carries, we multiply the number of electrons removed by the elementary charge of an electron.
The charge (Q) on the balloon can be calculated using the formula:
Q = n × e
Where:
n is the number of removed electronse is the elementary charge per electron (1.6 × 10⁻¹⁹ C)Let's plug in the values into the formula:
Q = 12000 × 1.6 × 10⁻¹⁹ C
Q = 1.92 × 10⁻¹⁵ C
Converting coulombs (C) to microcoulombs (µC) by multiplying by 10¶ gives:
Q = 1.92 × 10⁻¹⁵ C × 10¶ µC/C
Q = 1.92 µC
The balloon will carry a charge of 1.92 µC after 12000 electrons have been removed.
What causes a meteor shower?
Answer: Meteor showers occur when the earth in its orbit around the Sun passes through debris left over from the destruction of comets.
Explanation:A meteor is a particle broken off an asteroid or comet orbiting the Sun, it burns up as it enters the Earth's atmosphere, creating the effect called shooting star. Cosmic debris of meteor is known as meteoroids. These meteoroids, entering Earth's atmosphere, at extremely high speeds on parallel trajectories is an event known as meteor shower.
If the specimen is loaded until it is stressed to 65 ksi, determine the approximate amount of elastic recovery after it is unloaded. Express your answer as a length. Express your answer to three significant figures and include the appropriate units.
Answer:
ER = 0.008273 in
Explanation:
Given:
- Length of the specimen L = 2 in
- The diameter of specimen D = 0.5 in
- Specimen is loaded until it is stressed = 65 ksi
Find:
- Determine the approximate amount of elastic recovery after it is unloaded.
Solution:
- From diagram we can see the linear part of the curve we can determine the Elastic Modulus E as follows:
E = stress / strain
E = 44 / 0.0028
E = 15714.28 ksi
- Compute the Elastic strain for the loading condition:
strain = loaded stress / E
strain = 65 / 15714.28
strain = 0.0041364
- Compute elastic recovery:
ER = strain*L
ER = 0.0041364*2
ER = 0.008273 in
The approximate amount of elastic recovery after unloading a stressed specimen is zero.
Explanation:To determine the approximate amount of elastic recovery after unloading a stressed specimen, we need to consider the concept of elastic deformation. Elastic deformation refers to the temporary elongation or compression of a material when a stress is applied to it, and it returns to its original shape once the stress is removed.
Since the question does not provide specific information about the material or its elastic modulus, we cannot determine the exact amount of elastic recovery. However, we can generally say that the elastic recovery would be close to the original length of the specimen before it was loaded.
Therefore, we can assume that the approximate amount of elastic recovery would be zero, as the specimen would return to its original length.
In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 10.1 oC. The temperature at the inside surface of the wall is 20.8 oC. The wall is 0.18 m thick and has an area of 8.9 m2. Assume that one kilowatt hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall
Answer:
17 hours
Explanation:
k = Thermal conductivity of concrete = 1.1 W/m°C
A = Area = [tex]8.9\ m^2[/tex]
l = Thickness = 0.18 m
[tex]\Delta T[/tex] = Change in temperature = 20.8-10.1
Power is given by
[tex]P=\dfrac{kA\Delta T}{L}\\\Rightarrow P=\dfrac{1.1\times 8.9\times (20.8-10.1)}{0.18}\\\Rightarrow P=581.961\ W[/tex]
Time required to produce 1 kWh
[tex]t=\dfrac{3600\times 10^3}{581.961}\\\Rightarrow t=6185.98153485\ s[/tex]
For one dollar
[tex]t=\dfrac{6185.98153485}{0.1}\\\Rightarrow t=61859.8153485\ s\\\Rightarrow t=\dfrac{61859.8153485}{60\times 60}\\\Rightarrow t=17.1832820412\ hours[/tex]
The time taken is 17 hours
A block of mass m = 150 kg rests against a spring with a spring constant of k = 880 N/m on an inclined plane which makes an angle of θ degrees with the horizontal. Assume the spring has been compressed a distance d from its neutral position. Refer to the figure. show answer No Attempt 25%
Part (a) Set your coordinates to have the x-axis along the surface of the plane, with up the plane as positive, and the y-axis normal to the plane, with out of the plane as positive. Enter an expression for the normal force, FN, that the plane exerts on the block (in the y-direction) in terms of defined quantities and g. 25%
Part (b) Denoting the coefficient of static friction by μs, write an expression for the sum of the forces in the x-direction just before the block begins to slide up the inclined plane. Use defined quantities and g in your expression ΣFx = 25%
Part (c) Assuming the plane is frictionless, what will the angle of the plane be, in degrees, if the spring is compressed by gravity a distance 0.1 m? 25%
Part (d) Assuming θ = 45 degrees and the surface is frictionless, how far will the spring be compressed, d in meters?
Answer:
Explanation:
given
spring constant k = 880 N/m
mass m = 150 kg
Normal force will be equal to the component of weight of mass m which is perpendicular to the inclined surface
= mgcosθ
So normal force
FN = mgcosθ j , as it acts in out of plane direction .
b )
Fricrion force acting in upward direction = μs mgcosθ
component of weight acting in downward direction = mgsinθ
restoring force by spring on block in downward direction
= kd
= 880d
F( total ) = (μs mgcosθ - mgsinθ - 880d )i
c )
for balance
mgsinθ = kd
sinθ = kd / mg
= 880 x .1 / 150 x 9.8
= 88 / 1470
.0598
θ = 3.4 degree
d )
d = mgsinθ / k
150 x 9.8 sin45 / 880
= 1.18 m
The problem involves the equations of force related to a block on an inclined plane with a spring. The solution involves using concepts of statics, the restoring force of a spring, the force of gravity on an inclined plane and trigonometric functions to derive the formulas and find the answers.
Explanation:Part (a) The normal force, FN, is the product of the gravitational motion and the cosine of the angle. Therefore, FN=mgcosθ.
Part (b) Just before the block begins to slide up the plane, the sum of the forces in the x-direction is equal to the difference between the restoring force of the spring and the force due to gravity along the plane. Therefore, ΣFx = k*d - mgsinθ.
Part (c) For a frictionless plane, the angle of the plane is found by observing that the force due to gravity must be equal to the restoring force of the spring, which gives θ = arcsin(k*d/(mg)). To get the angle in degrees for d = 0.1 m, you would plug in the values: θ = arcsin(880*0.1/(150*9.81)) in radians, and convert to degrees.
Part (d) If θ = 45 degrees and the surface is frictionless, the distance the spring will be compressed, d, can be found from the equation mg*sinθ = k*d, which gives d = m*g*sinθ/k. Substituting in these values, d = 150*9.81*sin(45)/880.
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You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind and you perceive the frequency as 1370 Hz. You are relieved that he is in pursuit of a different speeder when he continues past you, but now you perceive the frequency as 1330 Hz. What is the speed of the police car? The speed of sound in air is 343 m/s.
Answer:
Explanation:
Given
Apparent frequency [tex]f'=1370\ Hz[/tex]
Velocity of sound [tex]v=343\ m/s[/tex]
speed of observer [tex]v_o=35\ m/s[/tex]
Using Doppler effect Apparent frequency when source is approaching is given by
[tex]f'=f(\frac{v-v_0}{v-v_s})[/tex]
[tex]1370=f(\frac{343-35}{343-v_s})---1[/tex]
Apparent frequency when source moves away from observer
[tex]f''=f(\frac{v+v_0}{v+v_s})[/tex]
[tex]1330=f(\frac{343+35}{343+v_s})---2[/tex]
Divide 1 and 2 we get
[tex]\frac{f'}{f''}=\frac{\frac{343-35}{343-v_s}}{\frac{343+35}{343+v_s}}[/tex]
[tex]\frac{1370}{1330}=\frac{343-35}{343-v_s}\times \frac{343+v_s}{343+35}[/tex]
[tex]v_s=40\ m/s[/tex]
Thus speed of sound of police car is 40 m/s
The problem involves the Doppler effect and can be solved by applying the relevant formulas for when the source of sound is approaching and when it is receding. By setting up a system of two equations with the speed of the police car as the unknown, one can solve for it algebraically.
Explanation:This is a classic problem related to the Doppler effect, which describes the change in frequency of a wave in relation to an observer moving relative to the source of the wave. It requires us to know some principles about sound waves, including that their speed in the medium is constant, and their frequency and wavelength are inversely proportional.
To solve the problem, we need to apply the formula of the Doppler effect both when the police car is approaching and when it is moving away. The formula for the perceived frequency (f) when the source is moving towards the observer in a medium, like air, is given by f = f0*(v + vo) / (v - vs), where f0 is the emitted frequency, v is the speed of the medium (sound in this case), vo is the observer's speed, and vs is the source's speed.
When the source (police car) is moving away, the formula differs slightly and is given by f = f0 * (v - vo) / (v + vs). Here, using the frequencies when the car was approaching (1370 Hz) and moving away (1330 Hz), along with your speed (35.0 m/s) and the speed of sound (343 m/s), we have two equations with vs (the speed of the police car) as the unknown. This system of equations can be solved algebraically, yielding the speed of the police car.
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A motorcycle has a velocity of 15 m/s, due south as it passes a carwith a velocity of 24 m/s, due north. What is the magnitude anddirection of the velocity of the motorcycle as seen by the driverof the car?
a. 9 m/s, north
b. 9 m/s, south
c. 15 m/s, north
d. 39 m/s, north
e. 39 m/s, south
Answer:
(b) 9m/s south
Explanation:
Case 1: A motorcycle has a velocity of 15 m/s, due south
Case 2: A car with a velocity of 24 m/s, due north.
Let the velocity of the car due south = Vs↓
Let the velocity of the car due north = Vn↑
Magnitude of the velocity of the motorcycle as seen by the driver of the car = V
V = Vn - Vs
= 24m/s - 15m/s = 9m/s↓
The magnitude and velocity of of the motorcycle as seen by the driver of the car = 9m/s south
The correct option is B
e. 39 m/s, south
Explanation:Let the velocity of the motorcycle be [tex]V_{M}[/tex]
Let the velocity of the car be [tex]V_{C}[/tex]
Let the velocity of the motorcycle relative to the car be = [tex]V_{MC}[/tex]
According to relativity of velocities in one dimension;
[tex]V_{MC}[/tex] = [tex]V_{M}[/tex] - [tex]V_{C}[/tex] --------------------------(i)
Now, take;
south to be negative (-ve)
north to be positive (+ve)
Therefore, we can say that;
[tex]V_{M}[/tex] = -15m/s [since the velocity is due south]
[tex]V_{C}[/tex] = +24m/s [since the velocity is due north]
Now, substitute the values of [tex]V_{M}[/tex] and [tex]V_{C}[/tex] into equation (i) as follows;
[tex]V_{MC}[/tex] = -15 - (+24)
[tex]V_{MC}[/tex] = -15 -24
[tex]V_{MC}[/tex] = -39 m/s
Remember that we have taken;
south to be negative (-ve)
north to be positive (+ve)
Since the result we got is negative, it means the speed is due south.
Therefore, the speed of the motorcycle as seen by the driver of the car is 3.9m/s, due south.
If a dog has a mass of 20.1 kg, what is its mass in the following units? Use scientific notation in all of your answers.
Answer:
dog's mass in grams is [tex]20.1\times 10^3 grams[/tex]
dog's mass in milligrams is [tex]20.1\times 10^6 milligrams[/tex]
dog's mass in micrograms is[tex]20.1\times 10^9 micrograms[/tex]
Explanation:
dog has a mass of m= 20.1 kg
dog's mass in grams is given by [tex]20.1\times 1000 grams=20100 gms =20.1\times 10^3 grams[/tex]
dog's mass in milligrams is given by [tex]20.1\times 10^6 milli grams=20100000 milligrams= 20.1\times 10^6 milligrams[/tex]
dog's mass in micrograms is given by
[tex]20.1\times 10^9 micro grams=20100000000 micrograms= 20.1\times 10^9 micrigrams[/tex]
A cart starts at x = +6.0 m and travels towards the origin with a constant speed of 2.0 m/s. What is it the exact cart position (in m) 3.0 seconds later?
Answer:
At the origin (x' = 0 m)
Explanation:
Note: From the question, when the cart travels towards the origin, the magnitude of its exact position reduces with time.
The formula of speed is given as
S = d/t................. Equation 1
Where S = speed of the cart, d = distance covered by the cart over a certain time. t = time taken to cover the distance.
make d the subject of the equation,
d = St ................. Equation 2
Given: S = 2.0 m/s, t = 3.0 s
Substitute into equation 2
d = 2(3)
d = 6 m.
From the above, the cart covered a distance of 6 m in 3 s.
The exact position of the cart = Initial position-distance covered
x' = x-d............ Equation 3
Where x' = exact position of the cart 3 s later, x = initial position of the cart, d = distance covered by the cart in 3.0 s.
Given: x = +6.0 m, d = 6 m.
Substitute into equation 3
x' = +6-6
x' = 0 m.
Hence the cart will be at 0 m (origin) 3 s later
The cart will be at a position of 12.0 m after 3.0 seconds.
Explanation:The cart is initially at a position of +6.0 m and is moving towards the origin with a constant speed of 2.0 m/s. We can use the formula for position to find its exact position after 3.0 seconds.
The formula for position is position = initial position + (velocity × time).
Plugging the values into the formula, we get:
position = 6.0 m + (2.0 m/s × 3.0 s) = 6.0 m + 6.0 m = 12.0 m.
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From January 26, 1977, to September 18, 1983, George Meegan of Great Britain walked from Ushuaia, at the southern tip of South America, to Prudhoe Bay in Alaska, covering 30 600 km. What was the magnitude of his average speed during that time period
Answer:
average speed = 0.146 m/s
Explanation:
given data
distance = 30600 km
time = January 26, 1977 to September 18, 1983
solution
we get here time that is January 26, 1977 to September 18, 1983
so it is = 6 year and 7 months and 22 days
and that is = 2422 days = 2.09 × [tex]10^{8}[/tex] seconds
and distance is = 30600 km = 30600 × 10³ m
so here average speed will be as
average speed = [tex]\frac{distance}{time}[/tex] ...........1
average speed = [tex]\frac{30600*10^3}{2.09*10^8}[/tex]
average speed = 0.146 m/s
A support wire is attached to a recently transplanted tree to be sure that it stays vertical. The wire is attached to the tree at a point 1.50 m from the ground and the wire is 2.00 m long. What is the angle between the tree and the support wire?
Answer:
Explanation:
Given
Wire attached to the tree at a point [tex]h=1.5\ m[/tex] from ground
Length of wire [tex]L=2\ m[/tex]
From diagram,
Using trigonometry
[tex]\sin \theta =\frac{Perpendicular}{Hypotenuse}[/tex]
[tex]\sin \theta =\frac{1.5}{2}[/tex]
[tex]\theta =48.59[/tex]
Angle between Tree and support[tex]=90-48.59=41.41^{\circ}[/tex]
To find the angle between the tree and the support wire, we can use trigonometry. Given that the wire is 2.00 m long and attached to the tree at a point 1.50 m from the ground, the angle between the tree and the support wire is 41.1 degrees.
Explanation:To find the angle between the tree and the support wire, we can use trigonometry. The wire and the ground form a right triangle, with the wire as the hypotenuse and the vertical distance from the ground to the point of attachment as the opposite side. Using the Pythagorean theorem, we can find the length of the base of the triangle, which is the distance between the point of attachment and the tree.
Given that the wire is 2.00 m long and attached to the tree at a point 1.50 m from the ground, we can calculate the length of the base using the Pythagorean theorem: square root of (2.00^2 - 1.50^2) = 1.30 m.
Now we can use the trigonometric function tangent to find the angle between the tree and the support wire: tangent(angle) = opposite/adjacent, where the opposite side is 1.30 m and the adjacent side is 1.50 m. Solving for the angle, we get: angle = arctan(1.30/1.50) = 41.1 degrees (rounded to one decimal place).
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A gun is fired with angle of elevation 30°. What is the muzzle speed if the maximum height of the shell is 544 m? (Round your answer to the nearest whole number. Use g ≈ 9.8 m/s2.)
The muzzle speed of the gun, when fired at an angle of elevation of 30° and reaching a maximum height of 544 m, is approximately 329 m/s.
Explanation:The physics concept here is projectile motion. The muzzle speed of the gun can be calculated using the equation for the maximum height attained by a projectile, which is given by H = (V^2 * sin^2θ) / 2g, where V represents the muzzle speed, θ is the angle of elevation, and g is the acceleration due to gravity. Rearranging for V, and substituting the given values, we get:
V = sqrt((2 * H * g) / sin^2θ) = sqrt((2 * 544 m * 9.8 m/s^2) / sin^2 30°). Since sin 30° = 0.5, this leads to V = sqrt((2 * 544 m * 9.8 m/s^2) / (0.5)^2). The resulting muzzle speed, when calculated and rounded to the nearest whole number, is 329 m/s.
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