Quick answer: Friction is the contact force that resists sliding. This AP Physics 1 test on friction and inclines has 8 questions worth 20 marks, to do in 45 minutes: kinetic friction, box on a floor and sliding on a slope. The mark scheme is on a separate page; free printable PDF.
This test lasts 45 minutes and is worth 20 points. Use g = 9.81 m/s², show all working, include units and draw free-body diagrams whenever they help.
Level: AP Physics 1 (algebra-based) · Curriculum: AP P1 Unit 2
Question 1 Kinetic friction (1 mark)
State the equation for kinetic friction and define each symbol. (1 mark)Question 2 Box on a floor (3 marks)
An 8.0 kg box rests on a floor with μs = 0.60.- Calculate the maximum static friction force. (2 marks)
- State the friction force when a horizontal push of 40 N is applied. (1 mark)
Question 3 Sliding on a slope (3 marks)
A 6.0 kg block slides down a 20° slope with μk = 0.10. Calculate its acceleration. (3 marks)Question 4 Atwood machine (4 marks)
The figure shows masses of 5.0 kg and 3.0 kg over a frictionless pulley.- Calculate the acceleration of the masses. (2 marks)
- Calculate the tension in the string. (2 marks)
Question 5 Spring (3 marks)
A spring with k = 120 N/m is stretched by 0.080 m.- Calculate the force it exerts. (1 mark)
- Calculate the mass that would hang at rest at this stretch. (2 marks)
Question 6 Why μ is not constant (2 marks)
Explain why a larger force is needed to start a heavy crate sliding than to keep it sliding. (2 marks)Question 7 Stopping on the road (3 marks)
A car travelling at 20 m/s brakes with locked wheels on a road with μk = 0.70. Calculate the stopping distance. (3 marks)Question 8 Sled pulled at an angle (1 mark)
Explain why friction on a sled decreases when the rope is raised above the horizontal. (1 mark)
