A billiard ball of mass 0.155 kg is rolling directly away from you at 3.5 m/s. It collides with a stationary golf ball of mass 0.052 kg. The billiard ball rolls off at an angle of 15 deg. Clockwise from its original direction with a velocity of 3.1 m/s. What is the velocity of the golf ball?

Question

anonymous · Answer

Takes a while to get there. You need to use conservation of momentum in the 'directly away from you' direction, using vectors. Then use conservation in the direction perpendicular to that (as there was none before impact and there is after). You'll have two equations to solve for the two unknowns: velocity of the golf ball and the angle it travels at. My answer is 1.71m/s in a direction 28 deg. anticlockwise from straight on, but I rushed through the arithmetic on the back of a sheet...