LLuis Ramon, macho hunter, is out hunting javelina with a spear. A 20.9 kg boar charges at him at 12.68 m/s, and he calmly throws his 8.62 kg spear into the beast
at a rate of 29.5 m/s. What is the new velocity of the javelina?

Amoving electron has kinetic energy k1. after a net amount of work w has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) find w in terms of k1. (b) does your answer depend on the final direction of the electron's motion?