Starting and Stopping

Seeing how pushes and pulls can start things moving or bring them to a stop.

  • Define and explain Starting and Stopping in your own words
  • Use key terms such as force accurately
  • Apply what you have learned to new examples and questions
  • Avoid the common mistakes learners make with this topic

This lesson focuses on Starting and Stopping: seeing how pushes and pulls can start things moving or bring them to a stop.

Definition: Starting and Stopping

Seeing how pushes and pulls can start things moving or bring them to a stop.

Key ideas

Forces change how things move

A stationary object stays still until a push or a pull acts on it. A moving object keeps going in a straight line until a force changes its speed or direction. The bigger the push, the bigger the change — a gentle tap nudges a ball, while a hard kick sends it flying.

Gravity always pulls down

Drop a ball and it falls to the ground because Earth's gravity pulls it downwards. Gravity acts on everything, which is why what goes up must come down. It even keeps the Moon circling the Earth instead of drifting away.

Key term — force: A push or a pull. Forces can make things move, stop moving, change direction or change shape.

Which way will it move?

A toy boat floats in a paddling pool. Mia pushes the back of the boat gently with her hand. What happens?

A push acts on the boat in the direction Mia's hand moves. The water pushes back only a little, because water is smooth and slippery. The boat moves forwards, away from Mia's hand. If she pushed harder, the boat would move faster.

Answer: The boat moves away from Mia, in the direction of the push.

Common mistakes
  • Saying gravity pushes things down Gravity pulls things towards the Earth — the Earth attracts the object, so 'pull' is the correct word.
  • Believing a push has to touch something Magnets can pull metal objects without touching them, and gravity pulls without touching too.

Practice

Name the force that pulls a dropped apple to the ground.
It comes from the Earth.

Gravity.

Does a bigger push make a toy car travel further?
Think about what you feel when you push harder.

Yes — a bigger push gives the car more speed, so it travels further before friction stops it.

A marble rolls across a smooth table and falls off the edge. Which force makes it fall?
It acts downwards everywhere on Earth.

Gravity pulls the marble downwards once it is no longer supported by the table.

Give one example of a pull you do every day.
Think about opening something.

Answers vary: opening a door or drawer, pulling on socks, tugging a zip. A pull moves something towards you.

Quick check

Starting and Stopping — quick check

Which of these best defines "force"?

A push or a pull. Forces can make things move, stop moving, change direction or change shape.

Why does a sledge slow down on flat snow?

Friction between the sledge and the snow opposes its motion and slows it down.

Kicking a football is an example of a push or a pull?

A push — your foot shoves the ball away from you.
Key takeaways
  • Starting and Stopping: seeing how pushes and pulls can start things moving or bring them to a stop.
  • Forces change how things move: A stationary object stays still until a push or a pull acts on it.
  • friction: The force that slows things down when two surfaces rub against each other, like shoes gripping the ground.
  • Watch out for: saying gravity pushes things down