Directions: On this worksheet you will be practicing your knowledge of conservation of momentum.

Question 1 A 2.8-kg ball has a KE of 85.2 J. What is the ball's momentum?

18.5 kg m/sec170.4 kg m/secomit21.8 kg m/sec10.9 kg m/sec

Question 2 A 55-kilogram skater at rest on a frictionless rink throws a 2.8-kilogram ball, giving the ball a velocity of 7.8 m/s. Which value describes the skater's subsequent motion?

-19.74 m/sec-0.05 m/sec-3.06 m/secomit-0.4 m/sec

Question 3 A 3130-kg freight car moving at 7.8 m/sec collides and couples with an 7825-kg freight car which is initially at rest. The approximate common final speed of these two cars is

Question 4 A 5.5-g bullet moving at 206 m/sec is brought to a stop in 0.8 seconds when it strikes a tree. The average braking force exerted on the bullet by the tree is

-515 N-1.42 Nthere is not enough information to calculate the forceomit-0.91 N

Question 5 You push two objects, both initially at rest, with the same amount of force through the same distance. Object A has mass, m, while object B has mass, 4m.

omitA will gain 2 times as much KE as BA will gain 2 times as much momentum as BB will gain 2 times as much momentum as AB will gain 2 times as much KE as A

Question 6 A heavy and a light object are released from the same height and fall to the ground. Just before they strike the ground, they will have

none of the other choices are trueomitexperienced the same forcegained the same kinetic energygained the same amount of momentum

Question 7 A girl jumps upward from the surface of the earth. Does an external force act on system 'girl + earth'?

yes, because each participant (girl and earth) will accelerateno, the each participant (girl and earth) experience equal but opposite impulses and equivalent changes in momentumyes, because each participant (girl and earth) will experience a change in its momentumomitno, all forces in the diagram cancel each other and neither participant (girl and earth) is accelerated

Question 8 Running at 3.9 m/sec Jack, a 45-kg quarterback, collides with Leon, a 90-kg tackle, who is traveling towards him at 7.8 m/sec. Upon colliding, Leon continues to travel forward towards Jack, at 1.56 m/sec. How fast does Jack leave the collision?

16.38 m/sec-8.58 m/sec1.56 m/sec-3.12 m/secomit

Question 9 In which picture does Bronco have the greatest terminal velocity?