Exam practice
Exam questions
Write your answer. Then open the mark scheme and tick each point you made.
- Question 1 of 102 marks
A crate weighs 900 N. The area of its base is 3 m². Calculate the pressure it puts on the floor. Give the unit.
Mark scheme
- 900 ÷ 3 = 300
- N/m² (accept: newtons per square metre, or pascals)
- Question 2 of 102 marks
Explain why a sharp knife cuts more easily than a blunt one.
Mark scheme
- The sharp edge has a smaller area (touching the food)
- So the same force gives a bigger pressure
- Question 3 of 102 marks
Describe how the pressure in a liquid changes as you go deeper, and explain why.
Mark scheme
- The pressure increases with depth
- There is more liquid above, and its weight presses down
- Question 4 of 102 marks
A block of wood floats on water. A stone sinks. For each one, compare its weight with the upthrust on it.
Mark scheme
- Wood: the upthrust equals its weight (accept: the forces are balanced)
- Stone: its weight is bigger than the upthrust
- Question 5 of 102 marks
Explain why atmospheric pressure is lower at the top of a mountain than at sea level.
Mark scheme
- Atmospheric pressure is caused by the weight of the air above
- At the top of a mountain there is less air above (so less weight presses down)
- Question 6 of 102 marks
A spring is 6 cm long. With a 4 N weight hanging on it, it is 14 cm long. (a) Calculate the extension. (b) The spring follows Hooke’s law. Give the extension with a 2 N weight.
Mark scheme
- (a) 14 − 6 = 8 cm
- (b) 4 cm (half the force gives half the extension)
- Question 7 of 102 marks
A force of 30 N pushes down on a spanner, 0.2 m from the nut. Calculate the moment of the force. Give the unit.
Mark scheme
- 30 × 0.2 = 6
- N m (newton metres)
- Question 8 of 103 marks
A child who weighs 500 N sits 2 m to the left of the pivot of a see-saw. A child who weighs 400 N sits 2.5 m to the right. Use moments to show whether the see-saw balances.
Mark scheme
- Anticlockwise moment = 500 × 2 = 1000 N m
- Clockwise moment = 400 × 2.5 = 1000 N m
- The moments are equal, so it balances
- Question 9 of 102 marks
A force of 40 N pushes a trolley 6 m. Calculate the work done. Give the unit.
Mark scheme
- 40 × 6 = 240
- J (joules)
- Question 10 of 102 marks
Explain how a lever makes it easier to lift a heavy load.
Mark scheme
- You can use a smaller force than the weight of the load
- But your force has to move through a bigger distance than the load moves