34) A pulley has an initial angular speed of 12.5 rad/s and a constant angular acceleration of 3.41
rad/s2. Through what angle does the pulley turn in 5.26 s?
A) 113 rad
B) 22.6 rad
C) 42.6 rad
D) 19.3 rad
E) 160 rad
Answer: A
45) A potter's wheel has the shape of a solid uniform disk of mass
and radius 0.65 m. It
spins about an axis perpendicular to the disk at its center. A small 2.1 kg lump of very dense clay
is dropped onto the wheel at a distance 0.41 m from the axis. What is the moment of inertia of
the system about the axis of spin?
A) 1.8 kg ∙ m2
B) 1.5 kg ∙ m2
C) 0.40 kg ∙ m2
D) 2.5 kg ∙ m2
Answer: A
5) Three masses are located in the x-y plane as follows: a mass of 6 kg is at (0 m, 0 m), a mass of
4 kg is at (3 m, 0 m), and a mass of 2 kg is at (0 m, 3 m). Where is the center of mass (or center
of gravity) of the system?
A) (1 m, 2 m)
B) (2 m, 1 m)
C) (1 m, 1 m)
D) (1 m, 0.5 m)
E) (0.5 m, 1 m)
Answer: D
29) As shown in the figure, a 10.0 m long bar is attached by a frictionless hinge to a wall and
held horizontal by a light rope that makes an angle θ = 49° with the bar. The bar is uniform and
weighs
What distance x from the hinge should a 10.0 kg mass be suspended for the
tension in the rope to be 177 N?
Answer: 10 m
Var: 50+
11) A 0.10-kg ball, traveling horizontally at 25 m/s, strikes a wall and rebounds at 19 m/s. What
is the magnitude of the change in the momentum of the ball during the rebound?
A) 1.2 kg ∙ m/s
B) 1.8 kg ∙ m/s
C) 4.4 kg ∙ m/s
D) 5.4 kg ∙ m/s
E) 72 kg ∙ m/s
Answer: C
18) Two ice skaters suddenly push off against one another starting from a stationary position.
The 45-kg skater acquires a speed of 0.375 m/s relative to the ice. What speed does the 60-kg
skater acquire relative to the ice?
A) 0.50 m/s
B) 0.28 m/s
C) 0.38 m/s
D) 0.75 m/s
E) 0.00 m/s
Answer: B
53) A 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides
directly with a stationary seal of mass 200 kg. The seal grabs onto the whale and holds fast. What
is the speed of these two sea creatures just after their collision? You can neglect any drag effects
of the water during the collision.
A) 0.00 m/s
B) 3.0 m/s
C) 4.0 m/s
D) 5.0 m/s
E) 6.0 m/s
Answer: D
55) A car (of mass 1500 kg) and a small truck (of mass 2000 kg) collide suddenly at right angles
at an icy intersection. The car was originally traveling eastward at 20.0 m/s and the truck was
traveling northward at 20.0 m/s just before the collision took place. What is the speed of the
combined wreck just after the collision if the vehicles become enmeshed?
Answer: 14.3 m/s
56) Two vehicles approach a right angle intersection and then suddenly collide. After the
collision, they become entangled. If their mass ratios were 1:4 and their respective speeds as they
approached the intersection were both 13 m/s, find the magnitude and direction of the final
velocity of the wreck.
A) 11 m/s at 14° with respect to the original direction of the lighter car
B) 16 m/s at 76° with respect to the original direction of the lighter car
C) 11 m/s at 76° with respect to the original direction of the lighter car
D) 26 m/s at 76° with respect to the original direction of the lighter car
E) 16 m/s at 14° with respect to the original direction of the lighter car
Answer: C
7) You are driving at
acceleration?
A) 36.0 m/s2
B) 1.20 m/s2
C) 20.8 m/s2
D) 0.833 m/s2
Answer: A
on a freeway curve of radius
What is the magnitude of your
13) A 1000-kg car is moving at 30 m/s around a horizontal unbanked curve whose diameter is
0.20 km. What is the magnitude of the friction force required to keep the car from sliding?
A) 9000 N
B) 9800 N
C) 300 N
D) 900 N
E) 3000 N
Answer: A
17) A jet plane flying 600 m/s experiences an acceleration of 4.0 g when pulling out of a circular
dive. What is the radius of curvature of the circular part of the path in which the plane is flying?
A) 640 m
B) 1200 m
C) 7100 m
D) 9200 m
Answer: D
19) A Ferris wheel has radius 5.0 m and makes one revolution every 8.0 s with uniform rotation.
A person who normally weighs 670 N is sitting on one of the benches attached at the rim of the
wheel. What is the apparent weight (the normal force exerted on her by the bench) of the person
as she passes through the highest point of her motion?
Answer: 460 N
46) The figure shows a graph of the position x of two cars, C and D, as a function of time t.
According to this graph, which statements about these cars must be true? (There could be more
than one correct choice.)
A) The magnitude of the acceleration of car C is greater than the magnitude of the acceleration
of car D.
B) The magnitude of the acceleration of car C is less than the magnitude of the acceleration of
car D.
C) At time t = 10 s, both cars have the same velocity.
D) Both cars have the same acceleration.
E) The cars meet at time t = 10 s.
Answer: D, E
47) The graph in the figure shows the position of an object as a function of time. The letters H-L
represent particular moments of time.
(a) At which moment in time is the speed of the object the greatest?
(b) At which moment in time is the speed of the object equal to zero?
Answer: (a) J (b) I
Var: 1
27) A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus
increasing the vertical frictional force that the pole exerts on the fireman. When the force on his
hands equals his weight, what happens to the fireman?
A) The fireman comes to a stop.
B) The fireman descends with slower and slower speed.
C) The fireman descends with a smaller but non-zero acceleration.
D) The fireman continues to descend, but with constant speed.
E) The acceleration of the fireman is now upward.
Answer: D
30) In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale
are also massless.
A) exactly 2.0 N.
B) exactly 1.0 N
C) 0.50 N
D) 0.00 N
E) more than 19.6 N
Answer: B
Var: 1
33) Two boxes, A and B, are connected by a horizontal string S on a horizontal floor. A very
light wire pulls horizontally on box B, as shown in the figure, with a force of 100 N. The reaction
force to this pull is
A) the pull that box B exerts on string S.
B) the pull that string S exerts on box B.
C) the pull that string S exerts on box A.
D) the pull of box B on the wire.
E) the force that box A exerts on box B.
Answer: D
28) At target practice, a rifle bullet is fired at an angle of 30° below the horizontal with an initial
velocity of 800 m/s from the top of a cliff 80 m high. How far from the base of the cliff does it
strike the level ground below if air resistance is negligible?
Answer: 140 m