Take two marbles or steel balls of the same size and practice shooting one into the other. Make these observations:
a. If you produce a head-on collision with the second marble initially at rest, does the first marble come to a complete stop after the collision?
b. If the collision with a second marble occurs at an angle, is the angle between the paths of the two marbles after the collision a right angle (90°)?
c. If marbles of different sizes and masses are used, how do the results of parts a and b differ from those obtained with marbles of the same mass?