I am not a scientist but as far as I remember it's the one that has the most stored energy example:from the height of the fall,the velocity,it's weight,the impact and the material it's made of....bowling ball or golf ball? You decide ....which is the most resilient? Which one wants to resume it's original shape the most?
I think a Hypothesis is a statement or proposal that can be proven by further experimentation. The Hypothesis then might be, if a baseball, a basketball, a tennis ball and a golf ball are dropped from the same height, all of the balls will bounce to the same height. (This Hypothesis might not be true). The process of dropping each ball from the same height and measuring the height of the bounce would then prove or disprove the Hypothesis.