Question

what error could cause predicted distance to not match actual distance of a ball?

three balls at three different masses are shot at the same angke and force. the predictrd distance vs actual distance is far off. with the expectioj of the largest ball (slighty). what error would cause this?

Answer 1

If I understand your question correctly, the only reason or source of error why actual and expected distances are far off is the presence of air resistance

When calculating theoretical values, we often ignore the friction effect or may oversimplify the drag models but during experiment, the actual distances covered will be a lot less due to presence of air drag which will change in the acceleration in x - direction.

Remember, masses here will matter only if air resistance is NOT negligible.