Free-body diagrams and Newton's lawsEdexcel International A Level Physics: Mind map

Exam questions on Free-body diagrams and Newton's laws

1. A book of mass 1.5 kg rests on a horizontal table. The gravitational field strength is 9.81 N kg⁻¹.
   A student says that the weight of the book and the normal contact force of the table on the book are a Newton's third law pair because they are equal and opposite. Give two reasons why the student is wrong.2 marks
2. A van of mass 1500 kg travels along a straight, level road. The driving force from the engine is 3200 N and the total resistive force is 800 N.
   The driver stops accelerating and the driving force becomes zero. The resistive force is still 800 N. Calculate the magnitude of the deceleration of the van.2 marks
3. A person of mass 70 kg stands on the floor of a lift. The gravitational field strength is 9.81 N kg⁻¹.
   The lift accelerates upwards at 1.2 m s⁻². Calculate the force the floor exerts on the person.3 marks