The total mechanical energy of a system is equally divided between kinetic energy and potential energy. can never be negative. is constant only if conservative forces act. is either all kinetic energy or all potential energy, at any one instant. is constant only if nonconservative forces act. A skier, of mass 60. kg, pushes off the top of a frictionless hill with an initial speed of 4.0 m/s. How fast will she be moving after dropping 10. m in elevation? 15. m/s 0.15 km/s 0.20 km/s 49. m/s 10. m/s In an inelastic collision, the final total momentum is less than the initial momentum. the same as the initial momentum. insufficient information to answer more than the initial momentum. A handball of mass 0.10 kg, traveling horizontally at 25. m/s, strikes a wall and rebounds at 19. m/s. What is the change in the momentum of the ball? 1.2 N-s 72 N-s 5.4 N-S 1.8N-s 4.4 N-s Car A (mass = 1000 kg) moves to the right along a level, straight road at a speed of 6.0 m/s. It collides directly with car B (mass = 200 kg) in a completely inelastic collision. What is the momentum after the collision if car B was initially at rest? 10. KN-s to the right zero 6.0 KN-s to the right 8.0 KN-s to the left 2.0 KN-s to the right