Quick answer: Newton's second law states that the resultant force equals mass times acceleration, ΣF = ma. This Physics 11-12 test on friction and inclined planes has 8 questions worth 20 marks, to do in 40 minutes: Newton’s second law, friction and direction and pushed crate. The mark scheme is on a separate page; free printable PDF.
This test covers Newton’s second law with friction, inclined planes, connected bodies and lifts. Use a calculator, draw a free-body diagram wherever it helps and give units with every answer. Take g = 9.81 N/kg. The test is worth 20 marks.
Level: Physics grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB A.2
Question 1 Newton’s second law (1 mark)
State Newton’s second law in symbols and define each symbol. (1 mark)Question 2 Friction and direction (2 marks)
A box is pushed along the floor. State the direction of the friction on the box and explain why the static friction on a box that does not move is smaller than the maximum possible friction. (2 marks)Question 3 Pushed crate (3 marks)
A 30 kg crate is pushed along a level floor with a force of 150 N. The coefficient of kinetic friction is 0.25.- Calculate the friction force. (1 mark)
- Calculate the acceleration of the crate. (2 marks)
Question 4 Block on a slope (4 marks)
A 6.0 kg block slides down the rough slope shown. The coefficient of kinetic friction is 0.30.- Calculate the component of the weight along the slope. (1 mark)
- Calculate the normal reaction. (1 mark)
- Calculate the friction force. (1 mark)
- Calculate the acceleration. (1 mark)
Question 5 Joined trolleys (3 marks)
A 4.0 kg trolley and a 1.0 kg trolley are joined by a light string on a smooth surface. A horizontal force of 15 N pulls the 4.0 kg trolley.- Calculate the acceleration of the trolleys. (1 mark)
- Calculate the tension in the string. (1 mark)
- Explain why both trolleys have the same acceleration. (1 mark)
Question 6 Lift passenger (3 marks)
A passenger of mass 60 kg stands on a scale in a lift that accelerates downwards at 2.0 m/s².- Calculate the scale reading. (2 marks)
- State the scale reading when the lift moves at constant velocity. (1 mark)
Question 7 Static and kinetic (2 marks)
A car skids further when the wheels lock than when the driver applies the brakes gradually without locking. Explain this using static and kinetic friction. (2 marks)Question 8 Normal reaction on a slope (2 marks)
Explain why the normal reaction on a block on a slope is less than its weight. (2 marks)
