Plan the investigation
What students will do
Use the student handout to organize predictions, measurements, and explanations.
- Predict the patterns. Sketch the equal-time dot patterns for a steady sled and an accelerating car before running.
- Compare the graphs. Measure both vehicles at the same time and sketch their position, velocity, and acceleration graphs.
- Use slope and area. Determine the car’s acceleration from a velocity–time slope and each vehicle’s displacement from signed graph area.
- Match the motion. Give the car zero acceleration and the sled’s velocity. Predict and test which patterns match and which offsets remain.
What students will learn
- Connect equal-time dot spacing with changes in velocity.
- Determine acceleration and displacement from velocity–time graphs.
- Distinguish equal velocity at one instant from equal acceleration.
Common misconception
Do equal velocities mean equal accelerations?
Two objects can share a velocity at one instant while their velocities change differently.