This exam consists of 26 questions; 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 122. When the exam was given, the mean was 102.5; the median was 107. Click here to see the formula sheet that came with the exam.

A block sits at rest on a horizontal surface. It suddenly explodes into two pieces. A piece of mass 4 kg goes to the left and a piece of mass 10 kg goes to the right. Each block slides along the frictionless surface, then up a frictionless ramp. The speed of the 4 kg block is 10 m/s immediately after the explosion.

What is the speed of the 10 kg block immediately after the explosion?

(a) 0 m/s (b) 2 m/s (c) 4 m/s (d) 6 m/s (e) 8 m/s

(a) 0.9 m (b) 3.4 m (c) 4.5 m (d) 5.1 m (e) 7.3 m

(a) equal to h_{4}. (b) less than h_{4}. (c) larger than h_{4}.

(a) They move to the left. (b) They move to the right. (c) They do not move.

A ship of mass 150,000 kg and speed 8 m/s strikes a stationary iceberg of mass 10 times bigger than the mass of the ship. Assume that the forces exerted by the water on the ship and on the iceberg are negligible.

What is the resulting velocity of the iceberg if the ship and the iceberg are stuck together after the collision?

(a) 0.24 m/s (b) 0.31 m/s (c) 0.56 m/s (d) 0.73 m/s (e) 0.89 m/s

(a) larger than V (b) equal to V (c) smaller than V

A 1800-kg car undergoes a collision during 0.25 s with an average force of 120,000 N.

By how much does the momentum of the car change?

(a) 400 kg-m/s (b) 5000 kg-m/s (c) 10,000 kg-m/s (d) 20,000 kg-m/s (e) 30,000 kg-m/s

(a) 3 m/s (b) 7 m/s (c) 13 m/s (d) 17 m/s (e) 22 m/s

A uniform beam of length 3 meters and mass 90 kg is supported by two ropes, as shown below, and is in static equilibrium.

In which rope is the tension greater?

(a) the left rope (b) the right rope (c) the tension is the same in each rope

(a) 220.5 N (b) 250.1 N (c) 290.6 N (d) 314.2 N (e) 365.0 N

A uniform rod of length 4 m and of weight 5 N is supported at its extreme right end by a fulcrum as shown. A block of weight W = 10 N is sitting 1 m from the fulcrum. An upward force F is applied at the extreme left end.

What is the force F needed to keep the system in static equilibrium?

(a) 10 N (b) 40 N (c) 5 N (d) 2.5 N (e) 7.5 N

(a) greater. (b) less. (c) the same.

(a) 0.105 rad/s (b) 22.7 rad/s (c) 360 rad/s

A wheel of radius 0.2 m starts from rest at t = 0 and rotates with constant angular acceleration about its axis to an angular velocity of 12 rad/s at t = 3 s.

What is the angular acceleration of the wheel?

(a) 4 rad/s^{2} (b) 15 rad/s^{2} (c) 7.2 rad/s^{2} (d) 36 rad/s^{2} (e) 1.33 rad/s^{2}

(a) 2.9 (b) 3.7 (c) 1.5 (d) 8.6 (e) 6.9

(a) 4 m/s^{2} (b) 15 m/s^{2} (c) 7.2 m/s^{2} (d) 36 m/s^{2} (e) 1.33 m/s^{2}

A child is pushing a toy chest across a rough floor with a constant force of 140 N directed at 30° below the horizontal. The mass of the child is 20 kg and the coefficient of friction between the chest and the floor is 0.46. The chest is pushed a distance of 2.0 m at constant speed.

What is the work done by the force of the child?

(a) 31 J (b) 121.5 J (c) 62 J (d) 243 J (e) 486 J

(a) greater than W. (b) equal to W. (c) less than W.

A block of mass M = 3 kg with an initial speed of v_{0} = 15 m/s slides down a ramp of height h_{1} = 3 m above a horizontal surface, along the horizontal surface, then up a second ramp of height h_{2} = 5 m.

The net work done by gravity on the block between the first and second ramp is positive.

(T) True (F) False

(a) 9.2 m/s (b) 11.5 m/s (c) 18.2 m/s (d) 5.9 m/s (e) 13.6 m/s

(a) 564 J (b) 345 J (c) 56 J (d) 146 J (e) 272 J

A rope is attached to a block and a force is applied to pull the block up a rough incline at constant speed. The incline makes an angle of 30° with the horizontal. The tension in the rope is T=46 N, the mass of the block is M = 5 kg, and the block is pulled a distance D = 8 m up the incline.

What is the work done by gravity?

(a) –196 J (b) –100 J (c) 0 J (d) –172 J (e) –45 J

Block A has a mass of 4 kg . It is released from rest and slides down a frictionless incline of height h above the floor. The incline makes an angle of 30° with the horizontal. Block B, which has a mass of 2 kg, is released from rest from the same height h above the floor and free-falls to the floor.

Which block has the largest kinetic energy when it reaches the floor?

(a) Block A (the heavier block on the incline) (b) Block B (the lighter block in free-fall) (c) They both have the same kinetic energy.

(a) Block A (the heavier block on the incline) (b) Block B (the lighter block in free-fall) (c) They both have the same speed.

(a) Block A (the heavier block on the incline) (b) Block B (the lighter block in free-fall) (c) They both arrive at the same time.