8. A 0.170 kg) puck on ice is loaded into a horizontal spring-powered launcher, which compresses a spring with a force constant of 1450 Nm by 5.5 cm? The puck is then released and slides across the ice for some distance, before having a head on elastic collision with a 0.155 kg puck that is at rest. Draw and label a picture to define your directions. (a) What is the potential energy stored in the spring initially? (3) (b) What is the velocity of the 0.170 kg puck before the collision? Use work-energy concepts. (3) (c) What are the velocities of the two pucks after the collision? (4)