A single force that represents the effect of all the forces acting on an object.

The state of an object if there is no resultant force acting on it.

A drawing in which forces are drawn end–to–end, and to scale, which can be used to find a resultant force.

Forces in two dimensions

Combined science

In the Gravity in space unit, they will build on this knowledge to learn about centripetal forces, orbital motion, stellar evolution, red shift and the big bang.

In the Energy of moving objects unit, pupils learnt how to calculate the amount of energy of objects have because they are moving, stretched or in a gravitational field; and to calculate energy transfers using knowledge of energy conservation and dissipation.

Forces make things change

Which of the following does an object in equilibrium never do?

A duck is swimming in a straight line across the surface of a lake, at a steady speed. Which of the following free body diagrams correctly shows the forces acting on the duck?

A helicopter is in equilibrium in the air. Which of the following motions are possible?

Moving up at increasing speed, while also moving steadily to the right.

Moving to the left at decreasing speed, while also moving steadily upwards.

Moving to the left at decreasing speed, while also moving steadily downwards.

An aeroplane and its free body diagram are shown. Which of the following are possible descriptions of the aeroplane’s motion?

A spaceship in space uses two rockets to produce forces acting in two directions at the same time. Which of the following vector diagram shows how to find the resultant force?

The vector diagram shows the addition of three forces to find the resultant force. What is the magnitude of the resultant force?

The diagram shows a force arrow drawn on a grid of 1 cm squares. What is the magnitude of the force?

There is a law of physics which states that an object will remain at rest, or in motion in a straight line at constant speed, unless a resultant force is acting on it. What is the name of this law?

What is the magnitude of the resultant force in the diagram shown?

The object is moving to the left at constant speed.

The object is moving to the right at constant speed.

The diagram shows an object with a single force acting on it. Which of the following are possible descriptions of the object’s motion?

A child throws a ball straight up. Which of the following is a correct free body diagram of the ball as it travels upwards?

Exit Quiz