Resultant force test with answers for GCSE physics (free PDF download)

Quick answer: A resultant force is the single force that has the same effect as all the forces acting on an object. This Physics 9-10 test on resultant force has 8 questions worth 20 marks, to do in 45 minutes: resultant force, weight and reaction and forces on a line. The mark scheme is on a separate page; free printable PDF.

This test covers types of force, free-body diagrams, resultant forces along a line and at right angles, and equilibrium. Show every step, give directions and include units. Calculators are allowed.

Level: Physics grades 9-10 (GCSE · IGCSE · O Level · Class 9-10) · Curriculum: GCSE P5

Time: 45 minutes · 8 questions · Total: 20 marks · Calculator allowed

Contents

Question 1 Resultant force (2 marks)

Define the resultant force on an object. (1 mark)
State what you can say about the motion of an object when the resultant force is zero. (1 mark)

Question 2 Weight and reaction (3 marks)

A bag has a mass of 3.5 kg and rests on a table. Use g = 9.8 N/kg.

Write the equation for weight and calculate the weight. (2 marks)
State the reaction force of the table on the bag. (1 mark)

Question 3 Forces on a line (3 marks)

A trolley is pushed with 8.0 N to the right and 5.0 N to the left at the same time.

Calculate the resultant force and give its direction. (2 marks)
The 5.0 N force is removed. Calculate the new resultant. (1 mark)

Question 4 Reading a free-body diagram (3 marks)

The diagram shows the forces on a crate.

Calculate the resultant horizontal force. (1 mark)
State the resultant vertical force. (1 mark)
Describe the effect on the crate. (1 mark)

Forces on a crate.

Question 5 Perpendicular forces (3 marks)

A ring is pulled with 9.0 N east and 12 N north. Calculate the resultant force and its direction as an angle north of east. (3 marks)

Question 6 Constant speed (2 marks)

A cyclist rides at constant speed on a flat road. Explain what this tells you about the driving force and the resistive forces. (2 marks)

Question 7 Hanging lamp (2 marks)

A lamp of mass 2.0 kg hangs at rest from a cord. Calculate the tension in the cord. (2 marks)

Question 8 Non-contact forces (2 marks)

Name two forces that act without the objects touching and give one example of each. (2 marks)

Unit of force? — The newton (N).

Weight formula? — W = m g, with g = 9.8 N/kg.

Forces in opposite directions: resultant? — Subtract; the larger force gives the direction.

Forces in the same direction: resultant? — Add them.

What does zero resultant force mean? — Rest or constant velocity: equilibrium.

What does a free-body diagram show? — All forces on one object, as labelled arrows.

Resultant of perpendicular forces? — R = √(F₁² + F₂²), by Pythagoras.

Direction of friction? — Opposite to the sliding or intended motion.

Direction of the normal reaction? — At right angles to the surface, pushing out.

Name two non-contact forces. — Gravity and magnetic force.