Science Buddies: "Ask an Expert"

We are doing a science project on the effect of mass of a ball and the holes in a ball on distance traveled.
Will the heavier ball go farther because of F=MA or is acceleration constant and the force is changed by the pull back angle. Also dose the small whiffle ball go farther or does it actually have more air resistance.

The force in your equation, F=MA, is the force the catapult can apply to the ball. That is determined by how far back you pull the catapult arm. So, at a given pulled back position of the catapult arm, the force applied to the ball will be roughly the same. Because F=MA, we know that A=F/M. If F is always the same, and the ball gets heavier, that is M gets bigger, then A, the acceleration of the catapult arm, goes lower. So, you should expect the heavier ball to not go as far.

But you bring up an interesting point about the wiffle ball. The holes in it definitely affect air drag, and this will affect the distance the ball goes.

To run your experiment cleanly, to be able to determine how the weight, that is the mass, of the ball affects the distance it will fly, you'll need to use SOLID balls of the same size but different weights. I'd suggest using styrofoam spheres. You could hollow them out and put different amounts of lead fishing weights inside them, then cover over the hole with PlayDough, or something like that.

Good luck and have fun!