PHS Edexcel cP2 Forces and Motion KeyWords

The total force that results from two or more forces acting upon a single object.

• resultant force

• vector force

• scalar force

• total force

When the forces in opposite directions on an object are the same size so that there is a zero resultant force.

• balanced forces

• action-reaction forces

• equal forces

• forces of equilibrium

A force that causes objects to follow a circular path. The force acts towards the centre of the circle

• centrifugal force

• central force

• centripetal force

• circular force

When a situation is not changing because all the forces affecting it balance out.

• balanced

• equilibrium

• centred

• equal

The mass of an object multiplied by its velocity.

It is a vector quantity, with units kilogram metres per second (kg m/s).

• acceleration

• force

• momentum

• weight

The total distance in which a car stops, which is the sum of the thinking and braking distances.

• stopping distance

• braking distance

• stopping time

• thinking distance

A vehicle safety device in which part of the vehicle is designed to crumple in a crash, reducing the force of the impact.

• air bag

• seat belt

• bumper

• crumple zone

Pairs of forces on interacting objects.

These forces are always the same size, in opposite directions, and act on different objects.

• balanced forces

• action-reaction forces

• equilibrium forces

• force pairs

A measure of how strong the force of gravity is somewhere. It is the force on a 1 kilogram mass, so the units are newtons per kilogram (N/kg).

• weight

• gravitational field strength

• GPE

• gravitational potential energy

The distance travelled by a car during the time taken for the drive to react.

• stopping distance

• braking distance

• thinking distance

• reaction distance