Al. A puck of mass m, moving at a speed of v1 collides with an identical mass stationary puck. After the collision, one puck moves off at an angle Q1 with a speed of v1', and the other puck moves off at an angle (2 with a speed of v2'. a) What are the speeds v1' and v2' if Q1 + 92 = 90? Express your answers in terms of v1 and 91. [3 points] b) Is the collision inelastic or (totally) elastic? Support your answer with a calculation. [2 points]