A person stands on bathroom scales in a lift.
The weight of the person is 600 N.
Gravitational field strength (ggg) = 10 N/kg
Describe the force that forms an interaction pair with the weight of the person.
Describe the force that forms an interaction pair with the normal contact force of the scales on the person.
The lift accelerates upwards. The normal contact force of the scales on the person is now 660 N.
Calculate the acceleration of the person.
A student says:
'The weight of the person and the normal contact force of the scales on the person are an interaction pair, because they are equal and opposite when the lift is at rest.'
Use your answer to (b) to explain why the student is wrong.
93 exam-style questions on Edexcel GCSE Physics 9.1 Forces and vectors, covering 9.1.1 Interactions and types of force, 9.1.2 Vector and scalar quantities, and 9.1.3 Vector diagrams and free body diagrams. Each one has a worked solution and a mark scheme showing where the marks go.