# Modern Physics Multiple Choice Questions

1. Use the work-energy theorem to find the force required to accelerate
an electron (m = 9.11 x 10-31 kg) from rest to a speed of 1.50 x 107 m/s
in a distance of 0.0125 m.

a. 8.20 x 10-15 N
b. 5.47 x 10-22 N
c. 8.20 x 10-17 N
d. 1.64 x 10-14 N
e. 3.56 x 10-19 N

2. Use the work-energy theorem to find the force required to accelerate
an electron (m = 9.11 x 10-31 kg) from rest to a speed of 1.50 x 107 m/s
in a distance of 0.0125 m.

a. 8.20 x 10-15 N
b. 5.47 x 10-22 N
c. 8.20 x 10-17 N
d. 1.64 x 10-14 N
e. 3.56 x 10-19 N

3. A ceiling fan has five blades, each with a mass of 0.34 kg and length of
0.66 m. The fan is operating in its "low" setting at which the angular
speed is 9.4 rad/s. If the blades can be approximated as uniform thin
rods that rotate about one end, what is the total rotational kinetic

a. 35 J
b. 29 J
c. 23 J
d. 17 J
e. 11 J

4. The spring constant for the spring in a special cannon is 1800 N/m. In
cocking the cannon, the spring is compressed 0.55m. What is the initial
speed of a 7.0-kg cannonball at rest on the free end of the spring when
it is released?

a. 77 m/s
b. 140 m/s
c. 12 m/s
d. 8.8 m/s
e. 16 m/s

5. A cylinder with a radius of 0.120 m is placed between the plates of a
hydraulic press as illustrated in the drawing. A 4.45 x 105 -N force is
applied to the cylinder. What is the pressure on the end of the cylinder
due to the applied force?

a. 9.84 x 106 Pa
b. 3.13 x 105 Pa
c. 6.18 x 106 Pa
d. 5.34 x 104 Pa
e. 3.71 x 106 Pa

6. A child wants to pump up a bicycle tire so that its pressure is 2.5 x 105
Pa above that of atmospheric pressure. If the child uses a pump with a
circular piston 0.035 m in diameter, what force must the child exert?

a. 120 N
b. 240 N
c. 340 N
d. 930 N
e. 1300 N

7. The two dams are identical with the exception that the water reservoir
behind dam A extends twice the horizontal distance behind it as that of
dam B. Which one of the following statements regarding these dams is
correct?

a. The force exerted by the water on dam A is greater than that on
dam B.
b. The force exerted by the water on dam B is greater than that on
dam A.
c. Dam A is more likely to collapse than dam B if the water level
rises.
d. Dam B is more likely to collapse than dam A if the water level
rises.
e. The horizontal distance of the water behind the two dams does
not determine the force on them.

8. The density of ice is 0.92 g/cm3, and the density of seawater is 1.03
g/cm3. A large iceberg floats in Artic waters. What fraction of the
volume of the iceberg is exposed?

a. 0.080%
b. 11%
c. 89%
d. 92%
e. 99%

9. Alyssa went to her outside faucet to fill a 0.032-m3 bucket with water
to wash her car. Water exits with a speed of 0.64 m/s. The radius of the
faucet is 0.0075 m. How long does it take to fill the bucket completely?

a. 9.0 s
b. 17 s
c. 190 s
d. 280 s
e. 890 s

10. The coefficient of linear expansion of a certain solid is 9 x 10-6/C°.
Assuming this solid behaves like most solids, what is its coefficient of
volume expansion?

a. 9.1 x 10-6/C°
b. 27 x 10-36/C°
c. 27 x 10-6/C°
d. 729 x 10-6/C°
e. 729 x 10-36/C°

11. A 2.00-kg metal object requires 5.02 x 103 J of heat to raise its
temperature from 20.0°C to 40.0°C. What is the specific heat capacity
of the metal?

a. 63.0 J/(kg?C°)
b. 126 J/(kg?C°)
c. 251 J/(kg?C°)
d. 502 J/(kg?C°)
e. 1.00 x 103 J/(kg?C°)

12. A 0.20-kg lead shot is heated to 90°C and dropped into an ideal
calorimeter containing 0.50 kg of water initially at 20.0°C. What is the
final equilibrium temperance of the lead shot? The specific heat
capacity of lead is 128 J/(kg?C°), and the specific heat of water is 4186
J/(kg?C°).

a. 4.8°C
b. 20.8°C
c. 22.4°C
d. 27.8°C
e. 42.1°C

13 . Heat is added to a sample of water in an insulated container. Which
one of the following statements is necessarily true?

a. The temperature of the water will rise.
b. The volume of the water must decrease.
c. The mass of the system must decrease.
d. Under certain conditions, the temperature of the water can
decrease.
e. The type of change that will occur depends on the original
temperature of the water.

© SolutionLibrary Inc. solutionlibary.com 9836dcf9d7 https://solutionlibrary.com/physics/classical-mechanics/modern-physics-multiple-choice-questions-3ckf