A 0.22 kg billiard ball moving to the right at 2.2 m/s has a head-on elastic collision with another ball of equal mass moving to the left at 0.85 m/s. The first ball moves to the left at 0.85 m/s after the collision. a- Find the velocity of the second ball after the collision,
b- Verify your answer by calculating the total kinetic energy before and after the collision.

Car batteries are often rated in amp-hours. this rating indicates the quantity of charge that can pass through the battery before the battery's chemical energy must be restored by the car's generator or some other source. the amp-hour unit is convenient for simple calculations. for example, a 60-amp-hour battery can supply a current of 1.0 a for 60 h (or 60 a for 1.0 h) before going dead. find the energy stored in the following. (a) a 58 a-h, 10 v car battery(b) a 1.3 a-h, 1.7 v flashlight battery