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PHYS 1112 Sample Questions from Previous Final Exam
1. A 3.00 kg box sits in a train moving at a constant velocity along the +x direction. The train started
to decelerate at a rate of −4.00 m/sec2. If the static friction coefficient between the box and the
train floor is sµ = 0.200 and the kinetic friction coefficient is kµ = 0.150, the box would
A. Remain sitting on the train floor without moving
B. Move along the +x direction relative to the train floor at a uniform speed of 2.53 m/sec
C. Accelerate relative to the train floor along the +x direction at a rate of +7.59 m/sec2
D. Move along the –x direction at a uniform speed of 7.59 m/sec
E. Accelerate relative to the train floor along the +x direction at a rate of +2.53 m/sec2
2. During a rainy day, a car is driven at a uniform speed v along a circular race course with radius
R=500 m. The race course is banked at an angle 25.0o. Suppose at some point the race course is
very slippery so that the static friction coefficient between the tire and the road is nearly zero,
what is a safe speed v for the car not to slip sideways?
A. v should be as small as possible
B. v=47.8 m/sec
C. v=66.6 m/sec
D. If the friction coefficient is zero, the car is going to slip sideways no matter at what speed
E. v is dependent on the mass of the car, hence there is not enough information to determine
the safe speed
3. Earth circulates around the Sun in a nearly circular orbit with a radius r=1.5×1011 m. Since it
takes T= 365.2 days (=31.55×106 sec) to complete one orbit, the mass of the sun, Ms, is given by
the expression (with G being the gravitational constant)
A. not enough information for its determination
B. 2 32 /sM r GTπ=
C. 3 22 /sM r GTπ=
D. 2 2 3/ 4sM GT rπ=
E. 2 3 24 /sM r GTπ=
4. A ball with mass m=0.1 kg is traveling along the positive x direction with vx=30 m/sec. It is hit by
an impulse J=3 N sec along the positive y direction. Its final speed is
A. 60 m/sec
B. 90 m/sec
C. 30 2 m/sec
D. 60/ 2 m/sec
E. 30/ 2 m/sec
5. A box that has a mass of 3.0 kg is dropped from a certain height and hit a spring with a spring
constant k=300 N/m. At the point of contact, the box has a speed of 1.0 m/sec, and it is stuck to
the spring. What is the resulting amplitude A and period T of oscillation? Assume the mass of the
spring to be negligible.
A. A=1.4 cm and T=10 sec
B. A=14 cm and T=0.63 sec
C. A=14 cm and T=10 sec
D. A=1.4 cm and T=0.63 sec
E. A=14 cm and T=0.1 sec
6. A satellite orbits the Earth in a circular orbit with radius r and speed v. Suppose the orbiting
radius is increased by a factor of 2, in order to stay in a stable orbit the orbiting speed must
A. 2v
B. / 2v
C. / 2v
D. 2v
E. Remain the same
7. This question is removed
8. This question is removed
9. A mass is attached to one end of a spring whose other end is fixed. The mass oscillates
periodically on a frictionless surface. It is suddenly hit by an impulse along its motion direction.
What would be the change in its oscillatory motion?
A. Both the period and amplitude would change
B. The period would not change, but the amplitude will change
C. Not enough information to determine the change
D. The amplitude would not change, but the period is changed
E. A., B., and D. are all possible, depending on the magnitude of the impulse
10. Assume that the Earth is orbiting the sun in a perfectly circular orbit. If the Earth is hit by a huge
meteorite but its orbiting angular momentum is not changed (this can be the case if the hit is
along the radial direction of the orbit), what would be the change in Earth’s orbit?
A. No change
B. Earth would move in a circular orbit with a larger radius
C. Earth would move in a circular orbit with a smaller radius
D. Earth’s orbit would not change, but its period is lengthened
E. Earth’s orbit would become elliptical
11. Earth is rotating about its north-south axis with a period of 24 hours. The density of the Earth is
not uniform. Generally the density is higher in the core than on the surface. If the mass of the
Earth is re-distributed so that the density is the same everywhere, its rotational period should be
A. longer than 24 hours
B. shorter than 24 hours
C. the same
D. not enough information to determine the outcome
E. either A. or B., dependent on whether there is energy dissipation during the mass re-
distribution
12. A block is sliding down an inclined plane that makes an angle α with the flat surface. The block
and the inclined plane has a kinetic friction coefficient 0.15kµ = . The block is seen to slide
down with a constant speed. What is the angle α ?
A. 8.5o
B. 81o
C. Dependent on the mass of the block, hence insufficient information
D. Not possible to slide down with a constant speed
E. 10o
13. A block with mass 0.50 kg moving at vx=1.0 m/sec collides head on with another block with mass
1.0 kg moving at vx= − 1.0 m/sec. Suppose the collision is inelastic and can therefore dissipate
energy, what is the maximum amount of energy that can be dissipated? Hint: what kind of
collision (elastic, inelastic, completely inelastic) should it be?
A. 0.75 J
B. 0.25 J
C. 0.67 J
D. 0.38 J
E. None of the above
14. Suppose future technology can realize a deep tunnel for bullet trains under the Pacific Ocean,
linking China and the United States. If air resistance and rail friction can be minimized, which of
the following statements must be false?
A. The train can utilize Earth’s gravity for acceleration and deceleration
B. The train can use less energy compared to traveling on the surface
C. The gravitational potential energy of the train is lower on the surface than at the deepest
point in the tunnel
D. Theoretically, the train can execute an oscillatory motion between the two ends of the
tunnel
E. The weight of the train can vary over the course of travel
15. Which of the following is a false statement?
A) In a transverse wave the particle motion is perpendicular to the direction of travel of the
wave.
B) Not all waves are mechanical in nature.
C) The speed of a wave and the speed of the vibrating particles that constitute the wave are
different entities.
D) Waves transport energy and matter from one region to another.
E) A wave in which particles move back and forth in the same direction as the wave is moving
is called a longitudinal wave.
16. Two sinusoidal waves of the same period, with amplitudes of 5.0 mm and 7.0 mm, travel
in the same direction along a string; they produce a resultant wave with an amplitude of 10.0
mm. The phase constant of the 5.0 mm wave is 0. The phase constant of the 10.0 mm wave is
0.708 rad. What is the phase constant of the 7.0 mm wave?
(A) π/6
(B) π/3
(C) 1.2
(D) 1.5
(E) 2.0