This question is blowing my mind, can anyone help? A ball is shot out of a projector by a spring and into a hollow ballast which then swings upwards 2.5 cm. The ball has a mass of 0.10 kg, the ballast has a mass of 0.50 kg, and the spring constant is 500 N/m. a. How fast is the ballast-ball system moving immediately after impact? b. How fast was the ball moving immediately before impact? c. How far was the spring compressed in order to release the ball with this speed?