A moving white hockey puck collides elastically with a stati…

A moving white hockey puck collides elastically with a stationary red hockey puck on a frictionless horizontal surface. No net external force acts on the two-puck system. Select all of the following statements that must be true for this collision.   (1) The kinetic energy of the white puck is conserved (same before and after the collision). (2) The linear momentum of the white puck is conserved. (3) The linear momentum of the two-puck system is conserved.

You and your friend are both standing on a horizontal fricti…

You and your friend are both standing on a horizontal frictionless surface. To get your friend’s attention, you throw a ball due west at your friend as shown below. The ball bounces elastically off your friend’s back. Which one of the following statements is true about this situation?  

A motorcycle and a truck are both moving in the same directi…

A motorcycle and a truck are both moving in the same direction in adjacent lanes on a highway. At a particular instant, the speed of the motorcycle is four times as large as the speed of the truck v. At that instant, the motorcycle is accelerating forward while the truck is moving at a constant velocity. Which one of the following statements best describes which vehicle has a larger momentum at that instant?