Newton's laws of motionAQA A-Level Physics: Flashcards

What these 12 flashcards ask

State Newton's first law.
State Newton's second law for constant mass.
State Newton's third law.
Why do third-law pairs never cancel each other?
Define the newton.
What does zero resultant force tell you about velocity?
What is inertia?
What is a free-body diagram?
What is the weight component down a slope at angle θ?
A 70 kg person is in a lift accelerating upwards at 1.5 m s⁻². What do the scales read?
What is the third-law pair of the weight of a book on a table?
How do you find the tension between two connected bodies?

Exam questions on Newton's laws of motion

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
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
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

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).