Physics 101 Exam 1
NAME ______________________
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1. In the situation below, a person pulls a string attached to block A, which is in turn attached to another,
heavier block B via a second string. (a) Which block has the larger acceleration? (b) How does the force
of string 1 on block A compare with the force of string 2 on block B? Explain your answers.
Physics 101 Exam 1
NAME ______________________
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2. A child slides down a slide that is inclined at an angle θ with respect to the ground. At the bottom,
her speed is half what it would have been if the slide had been frictionless. What is the ratio of the
acceleration she actually experienced to the acceleration she would have experienced on a frictionless
slide? Derive an expression for the coefficient of kinetic friction, µk, between the slide and the child in
terms on the angle, θ.
θ
Physics 101 Exam 1
NAME ______________________
3/7
2. Two blocks sitting on a frictionless table are pushed from the left by a horizontal force, as shown
below.
F
m1
m2
(a) Draw a free-body diagram for each of the blocks. (b) Express, in terms of the quantities given in the
figure, the force of contact between the two blocks. (c) What is the acceleration of the blocks?
Suppose now that, instead of a force on the left block, a force of equal magnitude but opposite direction
is applied to the block on the right.
m1
m2
F
(d) What is the force of contact between the two blocks in this case? (e) What is the acceleration of the
blocks? (f) Do your answers to parts b through e make sense? Explain.
Physics 101 Exam 1
NAME ______________________
5/7
4. A block is heading up a ramp with an initial speed of 4 m/s. The ramp is inclined at an angle of 37o
with respect to the horizontal table. The coefficient of kinetic friction between the block and the ramp
is µk = 0.25. How far up the ramp will it go? How much time elapses as the block travels up the ramp
and back down to its starting point? [sin(37o) = 0.6, cos(37o) = 0.8]
Physics 101 Exam 2
NAME ______________________
3/8
2. Identical constant forces push two identical masses A and B continuously from a starting line to a
finish line. If A is initially at rest and B is initially moving to the right, which mass has the larger
change in momentum? Which mass has the larger change in kinetic energy? Explain your answers.
v0 = 0
A
v0 = 0
B
start
finish
Physics 101 Exam 2
NAME ______________________
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4. Two blocks of mass m and 3m, resting on a frictionless table, are connected by a stretched spring and
then released. (a) Is there a net external force on the system? (b) Determine the ratio of their velocities.
(c) What is the ratio of their kinetic energies? (d) Describe the motion of the center of mass of the
system.
Physics 101 Exam 2
NAME ______________________
2/8
1. Two 20-kg sleds are placed a short distance apart, one directly behind the other, on a frozen
(frictionless) pond. A 4-kg cat, standing on one sled, jumps across to the other and then immediately
back to the first. Both jumps are made at a horizontal speed of 3 m/s relative to the ice. Find the final
speeds of the two sleds.