Revise: Newton's LawsIdentifying balanced and unbalanced forces
Isaac Newton’s Laws of Motion describe how forces change the motion of an object, how the force of gravity gives weight to all masses, how forces cause acceleration and how forces work in collisions.
Identify whether the forces are balanced or unbalanced in each of the following cases.
Question
A Formula 1 car accelerating from the starting grid.
The car is accelerating. There is an unbalanced force acting.
Question
A cyclist braking.
When the brakes are applied the speed of the cyclist decreases. There is an unbalanced force acting.
Question
A satellite orbiting the Earth at constant speed.
The satellite's speed is constant but the direction in which it is travelling keeps changing. There is an unbalanced force acting on the satellite.
Question
A person resting in an armchair.
The person in the armchair is at rest and not moving. The forces are balanced.
Question
A lorry travelling at a constant speed on straight road.
The speed of the lorry is constant and the direction in which the lorry is travelling does not change. Therefore the forces acting on the lorry must be balanced.
