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Boss quiz

10 questions on the whole topic. You get one try at each.

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  1. Why do snowshoes stop you sinking into snow?

    • They make you weigh less
    • They make the pressure on the snow bigger
    • They warm the snow so that it sets hard
    • They spread your weight over a bigger area, so the pressure is smaller

  2. A box weighs 200 N. Its base has an area of 4 m². What pressure does it put on the floor?

    • 50 N
    • 204 N/m²
    • 50 N/m²
    • 800 N/m²

  3. A diver swims deeper. What happens to the water pressure on her?

    • It gets bigger
    • It stays the same
    • It pushes only on her back
    • It gets smaller

  4. A cork floats on water. What can you say about the forces on it?

    • It has no weight
    • Its weight is bigger than the upthrust
    • The upthrust is bigger than its weight
    • The upthrust equals its weight

  5. Why is atmospheric pressure lower at the top of a mountain?

    • Gravity stops working high up
    • The air is colder
    • There is less air above you, so less weight presses down
    • There is more air above you

  6. A spring follows Hooke’s law. A 1 N weight stretches it by 3 cm. How far does a 2 N weight stretch it?

    • 9 cm
    • 6 cm
    • 5 cm
    • 3 cm

  7. A force of 10 N pushes on a spanner, 0.5 m from the nut. What is its moment?

    • 20 N m
    • 5 N/m²
    • 5 N m
    • 10.5 N m

  8. A 400 N child sits 1 m to the left of the pivot of a see-saw. Where must a 200 N child sit to balance it?

    • 2 m to the right of the pivot
    • 4 m to the right of the pivot
    • 1 m to the right of the pivot
    • Half a metre to the right of the pivot

  9. A force of 50 N pushes a box 3 m across the floor. How much work is done?

    • 17 J
    • 53 J
    • 150 J
    • 150 N

  10. A lever lets you lift a heavy rock with a small push. What do you give up in return?

    • Your hand has to move further than the rock does
    • You have to do twice as much work
    • Nothing at all
    • The rock gets heavier
Answers
  1. They spread your weight over a bigger area, so the pressure is smaller. Same force, bigger area, smaller pressure.
  2. 50 N/m². Pressure = force ÷ area = 200 N ÷ 4 m² = 50 N/m².
  3. It gets bigger. Deeper down there is more water above, and its weight presses down. The pressure acts in all directions.
  4. The upthrust equals its weight. A floating object is in equilibrium: the upthrust balances its weight.
  5. There is less air above you, so less weight presses down. Atmospheric pressure is caused by the weight of the air above.
  6. 6 cm. Extension is proportional to force. Double the force gives double the extension.
  7. 5 N m. Moment = force × distance from the pivot = 10 N × 0.5 m = 5 N m.
  8. 2 m to the right of the pivot. 400 N × 1 m = 400 N m. The lighter child needs the same moment: 200 N × 2 m = 400 N m.
  9. 150 J. Work done = force × distance = 50 N × 3 m = 150 J.
  10. Your hand has to move further than the rock does. A lever trades force for distance: a smaller force moves through a bigger distance.