Measurements — read and record these values
Results table
Record your own measurements here. Nothing is calculated for you.
g
g
| Ball | Phase | Speed (cm/s) | Direction (°) | Mass (g) | Momentum (kg cm/s) |
|---|
Guided investigation
Work through the steps below to calibrate, mark and analyse your video, then use your measurements to think through the questions that follow. There are no right or wrong answers for the analysis questions — write what you observe in your own words.
- Calibrate. Pick "Calibrate", then click two points along a known length in the video (for example a ruler in the frame) and enter the real distance in centimetres.
- Mark. Pick "Mark", choose Ball A or Ball B, step the video to the frames you want, and click on each ball's position to record markers.
- Draw vectors. Pick "Vector", then click-and-drag to draw arrows showing each ball's direction of motion before and after the collision.
- Measure angles. Pick "Angle", then click on two of your arrows to read off the angle between them.
- What do you notice about the total momentum before and after the collision?
- How does the angle between the balls after the collision relate to the angle of approach?
- What sources of uncertainty affect your velocity measurements most?
- How would your results change if the balls had different masses?
- What assumptions are you making about the surface and the camera angle?