Newton's laws of motionAQA A-Level Physics: Mind map

Exam questions on Newton's laws of motion

1. A car of mass 1200 kg is accelerating along a straight, level road. At one instant the driving force from the road on the car is 3000 N and the total resistive force on the car is 800 N.
   The driver keeps the driving force at 3000 N. The resistive force increases as the car speeds up and the car eventually reaches a constant speed. Explain, using Newton's laws, why the car stops accelerating.2 marks
2. A person of mass 70 kg stands on bathroom scales on the floor of a lift. The scales read the normal contact force exerted on the person by the floor of the lift. Take g = 9.81 N kg⁻¹.
   The lift now moves upwards at a constant speed of 2.0 m s⁻¹. Determine the reading on the scales and explain your answer using Newton's first law.2 marks
3. A crate of mass 8.0 kg slides down a rough slope that is inclined at 25° to the horizontal. A constant frictional force of 12 N acts on the crate. Take g = 9.81 N kg⁻¹.
   State the three forces acting on the crate and give the direction of each.3 marks