Free Fall: Does Mass Change How Fast Things Drop?
1 · Predict
Drop a light, a medium, and a heavy ball from the same height at the same time. Which one hits the ground first?
- The heavier ball falls faster and lands first.
- All three fall at the same rate and land together.
- The lighter ball falls faster and lands first.
2 · Set Up
- Open the free-fall preset. You should see three balls of different sizes lined up at the same height.
- Attach the height probe to the medium ball and confirm all three balls start at the same y-position.
- Run the simulation and use the stopwatch/frame counter to time each ball's fall.
3 · Collect Data
| Mass (kg) | Elapsed Time (s) | Fall Speed (m/s) | Momentum (kg·m/s) |
|---|---|---|---|
| 1 | 1 | ||
| 3 | 1 | ||
| 6 | 1 |
Plot fall speed (y-axis) against elapsed time (x-axis) for all three balls on the same graph.
4 · Analyze
- Compare the fall speeds of the light, medium, and heavy balls at the same elapsed time. What do you notice?
- Using your data, compute the acceleration (Δspeed / Δtime) for each ball. How does it compare to g = 9.8 m/s²?
5 · Extend
- A feather and a bowling ball dropped in real air do NOT land together. What force, missing from this idealized sim, causes that difference?
- Astronauts on the Moon dropped a hammer and a feather and they landed together. Explain why the Moon is a better place than Earth to see this demonstration with real objects.
The Physics Behind This Experiment
Momentum
Even though all three balls share the same fall speed at a given time, their momenta differ because momentum scales with mass — this is why the heavy ball would do more damage on impact despite falling no faster.