Plan the investigation
What students will do
Start with a guided comparison, then plan an investigation, analyze a graph, and check a prediction.
- Compare mass pairs. Measure both hanging masses’ accelerations for different mass pairs and identify their shared acceleration magnitude.
- Design and collect. Choose at least five mass pairs with the same mass difference. Record total mass and acceleration during free motion.
- Analyze a linear graph. Transform total mass and acceleration to produce a straight line. Use its best-fit slope to estimate gravity.
- Explain and predict. Explain the roles of total mass and mass difference, then predict and test an unused mass pair.
What students will learn
- Apply a shared-motion constraint to connected objects.
- Distinguish driving force from total system mass.
- Use an inverse relationship to infer gravitational acceleration.
Common misconception
Does doubling both masses double acceleration?
Students distinguish scaling both masses from adding equal mass while preserving the mass difference.