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Grade 8 Beginner About 15 min Version 1 Awaiting review Premium

What can a force do? Shape and motion

A force is a push or a pull. Forces can change how an object moves: they can start it moving, make it go faster, slow it down, stop it or change its direction. Forces can also change an object's shape, by squashing, stretching, bending or twisting it. Some objects, like a rubber ball, spring back to their old shape when the force is removed (they are elastic). Others, like clay, stay changed (they are plastic).

What you will learn

  • Describe how a force can speed up, slow down, stop or turn a moving object.
  • Show that a bigger force causes a bigger change.
  • Tell elastic and plastic changes of shape apart.

Before you start

  • Know that force is measured in newtons (N).

Materials

  • A rubber ball, a ball of clay and a football

Equipment

  • A smooth table or floor
  • Force meter to give a measured push

Procedure

  1. Push the rolling rubber ball forwards and record what happens.
  2. Push it backwards, against its motion, and record it.
  3. Push it sideways and record its new direction.
  4. Push the clay ball and the rubber ball with 8 N and compare their shapes afterwards.

How this simulation is simplified

  • Every ball rolls at 1 m/s before the push, and friction is ignored.
  • Each push lasts 0.1 s.