← Back to the activity

Year 8 Science — Forces: contact and non-contact

Sort forces by whether they need the objects to touch, read a spring balance, and keep weight and mass apart.

Name: ________________________

  1. 1.What is the SI unit of force called? Give the one word.

  2. 2.A spring balance measures up to 10 N, with a bigger mark at each newton. Which mark is at 6 N?

    Mark the line with an X.

    012345678910

  3. 3.Sort these forces by whether the two objects have to be touching for the force to act.

    Groups: Contact force · Non-contact force

    • Electrostatic force
    • Friction
    • Gravitational force
    • Magnetic force
    • Muscular force

  4. 4.A 1 kg object weighs 10 N on the Earth, 25.4 N on Jupiter, 9 N on Venus and 3.8 N on Mars. What does the same object weigh on the Moon?

    • a) 9 N
    • b) 10 N
    • c) 1.6 N
    • d) 3.8 N

  5. 5.A ball is thrown straight up. Starting from The object moves straight up, put what happens next back into order.

    • Its speed goes on decreasing
    • The object moves straight up
    • It stops momentarily at the top
    • It falls back down, its speed increasing

  6. 6.A closed empty bottle is pushed down into a bucket of water and released. It shoots back to the surface. What has pushed it?

    • a) Upthrust, the upward force a liquid applies on an object placed in it
    • b) Friction between the bottle and the water
    • c) Muscular force still stored in the bottle from the push
    • d) The gravitational force of the Earth, acting upwards in water

  7. 7.An object placed in a liquid floats rather than sinks. What does the chapter say about the two forces on it?

    • a) The buoyant force acts downwards and the gravitational force upwards
    • b) The gravitational force is greater than the buoyant force
    • c) The buoyant force and the gravitational force are equal
    • d) There is no gravitational force acting on a floating object

  8. 8.Two balloons are rubbed with the same woollen cloth and hung near each other. What do they do, and why?

    • a) They move together, because they have picked up charges of opposite kinds
    • b) They move apart, because they have picked up charges of the same kind and like charges repel
    • c) They move together, because rubbing makes both of them sticky
    • d) They hang still, because rubbing wool on rubber charges neither of them

Answer key — Year 8 Science — Forces: contact and non-contact

  1. 1. newton
  2. 2. 6
  3. 3. Muscular force → Contact force; Friction → Contact force; Magnetic force → Non-contact force; Electrostatic force → Non-contact force; Gravitational force → Non-contact force
  4. 4. c) 1.6 N
  5. 5. 1. The object moves straight up 2. Its speed goes on decreasing 3. It stops momentarily at the top 4. It falls back down, its speed increasing
  6. 6. a) Upthrust, the upward force a liquid applies on an object placed in it
  7. 7. c) The buoyant force and the gravitational force are equal
  8. 8. b) They move apart, because they have picked up charges of the same kind and like charges repel