True-false questions are worth 2 points each, three-choice multiple
choice questions are worth 3 points each, five-choice multiple choice
questions are worth 6 points each. The maximum possible score is 95.
The exam period was 90 minutes. The mean score was 70.1; the median was
73. Click here to see page1
page2 of the formula sheet that came
with the exam.
Two identical disks slide on a horizontal frictionless surface. Disk
1 is initially traveling in the positive x-direction at a speed
v1. Disk 2 is initially traveling in the positive
y-direction at a speed v2. The disks collide and stick
together as shown in the figure below. The final speed of the two disks
is vf = 4 m/s, and they are traveling at an angle θ =
What is the initial speed v1 of disk 1 before the
(a) v1 = 7.5 m/s
(b) v1 = 9.1 m/s
(c) v1 = 11.3 m/s
(a) v2 = 0 m/s
(b) v2 = 1.1 m/s
(c) v2 = 2.7 m/s
A block with an initial speed v0, is at the start
of the hilly path shown in the figure below. There is no friction
between the block and the path, except on the 12-m long stretch between
points B and points C, where the kinetic friction coefficient is
μ = 0.43.
What is the minimum initial speed of the block so that it passes the
9 m hill at point A?
(a) v0 = 7.2 m/s
(b) v0 = 10.0 m/s
(c) v0 = 13.3 m/s
(d) v0 = 16.1 m/s
(e) v0 = 19.9 m/s
What is the speed of the block when it reaches point B?
(a) 10 m/s
(b) 20 m/s
(c) 40 m/s
(a) H = 4.4 m
(b) H = 9.9 m
(c) H = 12.2 m
(d) H = 15.3 m
(e) H = 23.3 m
(a) smaller than H/2.
(b) equal to H/2.
(c) larger than H/2.
Two identical putty balls are suspended from the ceiling by two
massless strings as shown in the figure below. The two strings have the
same length. Ball 1 is held at rest at point A, 0.4 m above ball 2,
which is freely hanging. Ball 1 is then released, collides with ball 2
at point B and and sticks to it. Both balls then go up together and
reach a maximum height h at point C.
When ball 1 travels from point A to point B, the work done by the
tension in the string is
(a) 0 m/s
(b) 1.7 m/s
(c) 2.8 m/s
(a) 0.1 m
(b) 0.2 m
(c) 0.4 m
(d) 0.8 m
(e) 1.6 m
(a) x = 2.0 m
(b) x = 2.3 m
(c) x = 2.5 m
A block of mass 0.25 kg moves at a speed of 1.5 m/s on a frictionless
horizontal surface. The block then hits a wall and bounces back. After
the collision with the wall, the block is traveling at the same speed
and in the opposite direction compared to before the collision.
Calculate the change in the kinetic energy of the block?
(a) ΔKE = 0 J
(b) ΔKE = 0.28 J
(c) ΔKE = 0.56 J
(a) 0 kg m/s
(b) 0.38 kg m/s
(c) 0.53 kg m/s
(d) 0.75 kg m/s
(e) 0.97 kg m/s
(a) 0.002 sec
(b) 0.003 sec
(c) 0.004 sec
A uniform beam 4 meters long is attached to the ceiling by a string 1.5
meters from the left end of the beam. The left end of the beam is
attached to the floor by another string. A 7 kg block is hanging from
the right end as shown in the figure.
What is TF the tension in the string attached to
the floor if the beam is massless?
(a) TF = 68.6 N
(b) TF = 114 N
(c) TF = 172 N
(a) TF = 150 N
(b) TF = 176 N
(c) TF = 208 N
(b) remain unchanged.
An 8 kg weight is attached to a 6 kg weight over a pulley as shown in
the figure. The pulley is a uniform disk with moment of inertial I = 2
kg m2 and radius R = 0.4 meters as shown in the figure. The
blocks start from rest, and after the 8-kg block has fallen a distance
h, it is observed to be traveling at 3 m/s.
What is the mass of the pulley?
(a) 15 kg
(b) 20 kg
(c) 25 kg
(a) Kp = 11 J
(b) Kp = 18 J
(c) Kp = 23 J
(d) Kp = 36 J
(e) Kp = 56 J
(a) h = 0.46 m
(b) h = 1.5 m
(c) h = 3.2 m
(d) h = 6.1 m
(e) h = 8.2 m
(a) > 3 m/s
(b) = 3 m/s
(c) < 3 m/s
(a) Wdisk > Whoop
(b) Wdisk = Whoop
(c) Wdisk < Whoop
Two masses are attached to a two-meter massless beam that has been
bent in the center and which is balancing on a fulcrum as shown in the
figure. The left side of the beam is horizontal and has a 1 kg mass
suspended from the end. The right side of the beam, makes an angle of
35° above the horizontal, and has an unknown mass suspended as shown
in the figure. The system is in equilibrium
Calculate m the mass of the object attached to the right side of
(a) 1 kg cos(35°)
(b) 1 kg sin(35°)
(c) 1 kg
(d) 1 kg / sin(35°)
(e) 1 kg / cos(35°)
(a) rotate counter clockwise (the 1 kg mass will go down).
(b) remain stationary.
(c) rotate clockwise (the 1 kg mass will go higher up).