I have two questions guys. When a large, heavy truck collides with a passenger car, the occupants of the car are more likely to be hurt than the truck driver. Why? There is a picture of a moving ping-pong ball striking a stationary bowling ball which shows the ping-pong ball hitting the bowling then going opposite direction while the bowling ball moves forward a little bit. On the second, there is a moving bowling ball striking a stationary ping-pong ball. Both go forward obviously. The question is: The kinetic energy of the Ping-Pong ball is larger after its interaction with the bowling ball than before. From where does the extra energy come? Describe the event in terms of conservation of energy. Thanks for the help.