| A2-2 | Vertical and horizontal motion in free fall. |
| Purpose: | To demonstrate that rate of vertical fall is independent of horizontal motion. |
| Description: | Shoot a ball horizontally and at the same time drop another ball vertically from the same height. The horizontally-launched ball falls and hits the ground at the same time as the dropped ball. This demonstrates that in free fall, the vertical motion is independent of the horizontal motion. |
| References: | |
| Equipment: | Spring apparatus that shoots one steel ball horizontally at the same time that it drops a second steel ball. In a commercial catalog, this apparatus is referred to as "second law of motion apparatus". Clamp and stand. |