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 114. The exam period was 90 minutes. The mean score was 67.8; the median was 68. Click here to see page1 page2 of the formula sheet that came with the exam.

Unless told otherwise, you should assume that the acceleration of gravity near the surface of the earth is 9.8 m/s^{2} downward and ignore any effects due to air resistance.

A solid, uniform cube 1 meter on a side is pushed against a narrow step on the floor (see figure); the block is then free to rotate about the axis marked with a solid black dot. A force F = 13 N is applied horizontally to the edge opposite the narrow step. What is the magnitude of the torque around the axis marked by the black dot due to the force F ?

(a) 7 N⋅m (b) 9 N⋅m (c) 11 N⋅m (d) 13 N⋅m (e) 15 N⋅m

(a) 8 N⋅m (b) 15 N⋅m (c) 32 N⋅m (d) 64 N⋅m (e) 74 N⋅m

Consider a ladder of length 5 m leaning against a house at an angle of 25° from the vertical. The mass of the ladder is 10 kg and the interaction between the wall and the ladder is frictionless. Assume the mass of the ladder is distributed uniformly. What is the normal force from the wall on the ladder?

(a) 22.8 N (b) 61.4 N (c) 77.5 N (d) 88.2 N (e) 98.3 N

(a) increases (b) decreases

(a) increased (b) decreased

(a) yes (b) no

A uniform solid disk of mass 3.2 kg and radius 0.25 m is spinning with an angular frequency of 40 rad/s around the axis at the center of mass, perpendicular to the disk. What is the magnitude of the disk's angular momentum?

(a) 1 kg m^{2}/s (b) 2 kg m^{2}/s (c) 4 kg m^{2}/s (d) 8 kg m^{2}/s (e) 16 kg m^{2}/s

(a) 2.5 rad/s^{2} (b) 5 rad/s^{2} (c) 7.5 rad/s^{2} (d) 10 rad/s^{2} (e) 20 rad/s^{2}

A ball falls vertically from the initial height of 2.1 m with no initial velocity to the floor and bounces vertically, reaching the highest point 1.7 m from the floor as illustrated. Take the origin of the potential energy of the ball to be that on the floor. The mass of the ball is 0.120 kg.

What is the loss of mechanical energy due to bouncing?

(a) 13% of the initial potential energy (b) 19% of the initial potential energy (c) 24% of the initial potential energy (d) 28% of the initial potential energy (e) 31% of the initial potential energy

(a) 0.27 N⋅s (b) 0.39 N⋅s (c) 0.84 N⋅s (d) 1.15 N⋅s (e) 1.46 N⋅s

(a) larger than the case with energy loss. (b) smaller than the case with energy loss. (c) Insufficient information is provided to give a definite answer.

In this event

(a) both energy and momentum are conserved. (b) energy is conserved, but not momentum. (c) momentum is conserved, but not energy.

(a) No, never. (b) Yes, (c) It depends on the details of the collision.

Two dry ice pucks slide on a horizontal, frictionless surface. Puck A, which is 2 kg, moves at speed 7 m/s in the positive x direction and Puck B, which is 1 kg, moves at speed 8 m/s in the negative y direction as shown in the figure. The pucks collide near the star in the figure. After the collision Puck B is moving in the positive x direction, while Puck A is moving in the direction that makes 45° with the positive x-axis as illustrated.

Find the speed of Puck A after the collision.

(a) 1 m/s (b) 2 m/s (c) 2√2 m/s (d) 4 m/s (e) 4√2 m/s

(a) 2 N⋅s (b) 4 N⋅s (c) 6 N⋅s (d) 8 N⋅s (e) 10 N⋅s

There is a slope with height h and the length of the slope L = 20 m as illustrated in the figure. A solid uniform cylinder of radium R = 0.2 m is at the top of the slope starting from rest. It rolls down the slope without any slip.

When the disk reaches the end of the slope, its center of mass has a speed of 4 m/s. What is the height h of the slope?

(a) 0.73 m (b) 0.92 m (c) 1.22 m (d) 1.4 m (e) 1.9 m

(a) 0.03 N⋅m (b) 0.06 N⋅m (c) 0.09 N⋅m (d) 0.12 N⋅m (e) 0.15 N⋅m

A) dropping in free fall B) rolling without slipping down a plane that has an angle α with the horizontal plane (the ground)

B) rolling without slipping down a plane that has an angle α with the horizontal plane (the ground)

(a) The kinetic energy of case A is greater than case B. (b) The kinetic energy of case B is greater than case A. (c) The kinetic energy in both cases is the same.

(a) 120 pounds (b) 200 pounds (c) 240 pounds (d) 300 pounds (e) 333 pounds

(a) More work is done by gravity in path A than in path B. (b) More work is done by gravity in path B than on path A. (c) The work done by gravity in both cases is identical.

(a) ball A (b) ball B (c) They both arrive at the bottom at the same time.

(a) 0.15 rad/s (b) 2.2 rad/s (c) 4.4 rad/s (d) 8.9 rad/s (e) 19.6 rad/s

(a) cylinder A (b) cylinder B (c) Both have the same rotational kinetic energy.

(a) The angular velocity of the smaller pendulum is greater than the angular velocity of the larger pendulum at the minimum position of the swinging pendulum. (b) The translational velocity of the larger pendulum is larger than the translational velocity of the smaller pendulum ball at the minimum position of the swinging pendulum. (c) The angular velocities of both pendulums are identical at the minimum position of the swinging pendulum.

(a) 2.9 m/s^{2} (b) 3.9 m/s^{2} (c) 4.9 m/s^{2} (d) 5.9 m/s^{2} (e) 6.9 m/s^{2}