7-34 A superball of mass 22 g rolls with a speed of 3.5 m/s toward another (stationary) superball of mass 27 g. If the balls have a head-on elastic collision, what are the velocities magnitudes and directions) of the balls after the collision?

[Ans. 3.1 m/s forward and 0.4 m/s backward]

 

As is the case with all problems in Physics, it is a good idea to make a drawing of the situation. For collisions the drawing should include the conditions before and after. Which drawing below is best?