Physics 1401

Question 1. Railroad car A rolls with velocity v_o right and makes a perfectly elastic collision with stationary car B of the same mass. Just after the collision, car A is observed to be at rest. The velocity of car B is observed to be

(a) v_o right    (b) v_o left    (c) 2v_o left    (d) v_o/2 right    (e) 0

 

 

Question 2. If the railroad cars of question 1 stick together after colliding inelastically, then their combined velocity will be

(a) v_o right    (b) v_o left    (c) 2v_o left    (d) v_o/2 right    (e) 0

 

 

Question 3. Jocko the clown (mass = 100 kg) stands motionless on ice skates. If some other clown throws a medicine ball (mass = 20 kg) with velocity v_o = 12 m/s right so that Jocko catches the ball, then Jocko and the ball will have a velocity (in m/s) of

(a) 0     (b) 2 right     (c) 2 left     (d) 4 right     (e) 4 left

 

 

Question 4. In question 3, if Jocko catches the ball momentarily and then throws it back to the other clown with velocity v = 8 m/s left, then Jocko's velocity (in m/s) will be

(a) 0     (b) 2 right     (c) 2 left     (d) 4 right     (e) 4 left

 

 

Question 5. A railroad diesel engine weighs four times as much as a freightcar. The engine with velocity v_o = 5 km/h left coasts into the freightcar that is initially at rest. If the engine and freightcar couple together their combined velocity (in km/h) will be

(a) 0     (b) 2 right     (c) 2 left     (d) 4 right     (e) 4 left

 

 

Question 6. A car with a mass of 1000 kg has a velocity of 30 m/s right. What braking force (in N) is needed to bring the car to a halt in 10 s?

(a) 0     (b) 3000 left     (c) 3000 right     (d) 10000 right     (e) 10000 left

 

 

Question 7. Two balls of the same mass, but made from different materials are selected for a collision experiment. In turn each ball is given the same velocity and allowed to collide with a wooden block. One ball collides elastically with the block while the other collides inelastically. The collision that produced the greater impulse was

(a) inelastic     (b) elastic     (c) both are the same       

 

 

Question 8. The impulse (in kg m/s) needed to stop a 10-kg bowling ball moving at 5 m/s is

(a) 0     (b) 5     (c) 10     (d) 50     (e) 500

First Name:		Last Name:
ID #: