Forces, motion and Newton’s laws
Learn Forces, motion and Newton’s laws for Year 9 pupils (ages 13–14). Free practice questions, lessons and worked examples — aligned to the UK National Curriculum.
What you'll learn
- 1
A resultant force changes how something moves. No resultant force means no change — not "no movement".
- 2
A spacecraft coasting with its engines off keeps going at a steady speed. Nothing is pushing it. It does not slow down because there is nothing to slow it.
- 3
A car travels at a steady 30 mph in a straight line. What is the resultant force?
- 4
Newton’s second law: F = m × a. A 1,200 kg car accelerating at 2 m/s² needs 1,200 × 2 = 2,400 N.
- 5
What force is needed to accelerate 50 kg at 4 m/s²?
- 6
Apply it: a skydiver speeds up, so air resistance grows. When it equals weight, the resultant force is zero and they fall at a constant terminal velocity — still moving fast, but no longer speeding up.
- 7
At terminal velocity, what is true of the forces?
Practise Forces, motion and Newton’s laws with Whizlo
Free AI-tutored lessons, unlimited practice questions, and progress tracking for ages 13–14. Aligned to the UK National Curriculum.