A 5.0 g coin sliding to the right at 25.0 cm/s makes an elastic
head-on collision with a 15.0 g coin that is initially at rest.
After the collision, the 5.0 g coin moves to the left at
12.5 cm/s.
a. Find the final velocity of the other coin.
b. Find the amount of kinetic energy transferred to the 15.0 g
coin.