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Grades 9 and 10 Advanced About 25 min Version 1 Awaiting review Premium

Motion graphs: distance-time and velocity-time

Motion is uniform when an object covers equal distances in equal times, and non-uniform when it speeds up or slows down. A distance-time graph shows where the object is at each moment: a straight sloping line means a steady speed, a curve that gets steeper means speeding up, and a flat line means the object is not moving. A velocity-time graph shows how fast it is going: a flat line means steady velocity, and a sloping line means acceleration. Acceleration = change in velocity ÷ time taken, a = (v − u) ÷ t, measured in m/s².

What you will learn

  • Plot distance-time and velocity-time graphs from measurements.
  • Tell uniform from non-uniform motion using the graphs.
  • Calculate acceleration from a change in velocity, a = (v − u) ÷ t.

Before you start

  • Know that speed = distance ÷ time.

Materials

  • Data from a car on a straight road

Equipment

  • Stopwatch and distance markers (a light gate or video in a real investigation)

Procedure

  1. Choose the steady car. Move the time slider and record the position and speed at least four times between 0 s and 10 s.
  2. Repeat for the car that speeds up.
  3. Choose the car that slows down and find the moment it stops.
  4. Compare the shapes of the lines on both graphs.

How this simulation is simplified

  • The road is straight and the car never reverses.
  • Each car keeps a constant acceleration.