Download PHY-1020 Exam 2 Spring/Summer 2006

PHY-1020
Exam 2
Spring/Summer 2006
Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.
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1. A coconut falls from a tree. The gravitational force does
a. negative work.
b. zero work
c. positive work
d. work of undefined sign
2. A comet is on an elliptical orbit around the Sun. While the comet is moving along its trajectory,
a. both its kinetic energy and angular momentum remain constant
b. its kinetic energy changes, but the angular momentum does not change
c. its kinetic energy remains constant, but the angular momentum changes
d. both its kinetic energy and angular momentum change.
3. A sled is sliding down a hill. The friction force
a. does positive work.
b. does zero work.
c. does negative work.
d. does work of undefined sign.
4. The work done by the net external force
a. is equal to the change of momentum of an object.
b. is equal to the change of kinetic energy of an object.
c. is equal to the change of potential energy of an object.
d. is equal to the change of the total energy of an object.
e. is always positive.
5. Only in elastic collisions is
a. the linear momentum conserved.
b. the total energy conserved.
c. the kinetic energy conserved.
d. the angular momentum conserved.
e. the potential energy conserved.
6. To change the angular momentum of the system
a. a net external force is needed.
b. a net external torque is needed.
c. an additional linear momentum is needed.
d. the impulse of a force is needed.
e. It is not possible to change the angular momentum of the system.
7. A person stands on a bathroom scale on two feet, and then on one foot.
a. In both cases the weight is the same, but in the second case the pressure is larger.
b. In both cases the weight is the same, but in the second case the pressure is smaller.
c. In both cases the weight and the pressure are the same.
d. Both the weight and pressure are larger in the second case.
e. Both the weight and pressure are smaller in the second case.
8. On one side a swimming pool is twice as deep as the other. The gauge pressure at a depth of 1 m on this side
is
a. twice as large as that at a depth of 1 m on the other side.
b. the same as that at a depth of 1 m on the other side.
c. twice as small as that at a depth of 1 m on the other side.
d. unrelated to that at a depth of 1 m on the other side.
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9. The pressure in a gas is due to __________ exchange between colliding atoms/molecules.
a. velocity
b. linear momentum
c. angular momentum
d. kinetic energy
e. potential energy
Exhibit 1
A force F1=100 N is pushing downwards on the left piston and compressing the fluid filling two cylinders
connected by a narrow hose, as shown in the figure. The area A1 is 1 cm2, and the area A2 is 10 cm2. Answer
questions on the basis of this information.
F1
F2
____ 10. Refer to Exhibit 1. The force exerted on the piston A2 by the fluid is ________ the force F1.
a. larger than
b. equal to
c. smaller than
d. unrelated to
____ 11. Refer to Exhibit 1. The pressure on the piston A2 by the fluid is ________ the pressure on the piston A1.
a. larger than
b. equal to
c. smaller than
d. unrelated to
3
____ 12. A balloon filled with helium (density 0.18 kg/m ) is floating first in cold air (density 1.29 kg/m3) and then in
hot air (density 0.73 kg/m3). If the volume of the balloon is the same in both cases, the buoyancy force in the
first case is ________ that in the second case.
a. larger than
b. equal to
c. smaller than
d. unrelated to
____ 13. The more heat the system has,
a. the larger its temperature is
b. the larger its internal energy is
c. the larger its entropy is
d. all the above
e. the system does not have heat.
____ 14. A person steps in a floating boat and the boat is now floating somewhat deeper than before. The buoyancy
force acting on the boat
a. increases.
b. does not change. c. decreases.
d. is zero.
____ 15. Heat is added to a gas. What can be done to maximize the increase of the internal energy of the gas?
a. Allow the gas to do positive work.
b. Do not allow the gas to do work.
c. Do positive work on the gas.
d. The increase of the internal energy is predetermined by the second law of
thermodynamics.
____ 16. A bimetallic strip is made of two materials that must have different
a. coefficients of linear expansion.
b. specific heat capacities.
c. heat conductivities.
d. phase transition points.
e. densities.
____ 17. Imagine that you are touching two similar pieces of wood and copper. Both are at the same temperature, say
150 oF. The sensations are nevertheless different: the wood does not seem to be as hot as the copper. This is
because the _________ of wood is less than that of copper.
a. specific heat capacity
b. density
c. heat
d. internal energy
e. heat conductivity
____ 18. The specific heat capacity of water is about twice the specific heat capacity of ice. From this information, the
amount of heat required to boil 1 kg of water is _____ the amount of heat required to melt 1 kg of ice.
a. 1/2
b. equal to
c. 2 times
d. unrelated to
____ 19. While water ice is melting, its temperature
a. is increasing.
b. is decreasing.
c. is constant.
d. can not be determined.
____ 20. The 6 a.m. dew on the grass evaporates by 10 a.m. Between 6 a.m. and 10 a.m.,
a. both the relative and absolute humidity of in the air increase.
b. the relative humidity of in the air increases, but absolute decreases
c. the relative humidity of in the air decreases, but absolute increases
d. both the relative and absolute humidity of in the air decrease.
e. none of the above.
____ 21. When the frequency of the source of a water wave increases, the distance between successive peaks in the
wave
a. remains unchanged.
b. increases.
c. decreases.
d. cannot be determined.
____ 22. When the frequency of the source of a water wave increases, the speed of the waves traveling in the water
a. remains unchanged.
b. increases.
c. decreases.
d. cannot be determined.
Matching Please match the following:
a. 0 oC
b. -18 oC
c. 212 oC
d. 32 oC
g__
a___
d___
a___
f___
23.
24.
25.
26.
27.
e.
f.
g.
h.
-273 oF
-273 oC
100 oC
-500 oC
the temperature of boiling water at the pressure of 1 atm.
the temperature of freezing water at the pressure of 1 atm.
the temperature of a hot summer day.
32 oF
absolute zero temperature.
28. Name at least two examples of physical phenomena explained by the Bernoulli principle.
The airlift force acting on a subsonic plane.
A trajectory of a spinning ball.