The gravitational force on something pulls it downwards, towards Earth.

When an object moves through a fluid there is a drag force that opposes the movement.

A resultant force is the overall effect of a set of forces on an object, taking their directions into account.

A parachute is used to increase the size of drag forces. This slows down the object it is attached to.

An object reaches a terminal velocity when the drag and gravitational forces are equal.

Changing the speed of a parachute

Science

Calculating speed

Measuring speed: practical

Measuring speed accurately

Reading distance-time graphs

Interpreting distance-time graphs

Changing speed

Newton's First Law

Streamlining

Comparing the speeds of different parachutes

In the Measuring and calculating motion unit, they will build on this knowledge to learn how to measure and calculate velocity and acceleration, and how to interpret velocity-time graphs. 

In the Forces unit, pupils learn to accurately describe and explain the actions of forces in a range of situations. 

This unit explores speed, forces, and motion, including effects on objects. It covers deriving equations, calculations, and distance-time graphs. Learn to use force arrows, identify balanced and unbalanced forces, and understand their impact on movement.

Moving by force

Physical activity and equipment requiring safe use

A force that pulls objects towards Earth.

The overall effect of a set of forces on an object.

A device used to increase drag during a fall.

Gravitational force is constant, drag force is constant.

Gravitational force decreases, drag force is constant.

Gravitational force increases, drag force is constant.

Gravitational force is constant, drag force increases.

Gravitational force is constant, drag force decreases.

Which of these describes what happens to the forces on a skydiver as they are speeding up?

A skydiver has a gravitational force of 700 N acting on them and a drag force of 600 N. What happens to the motion of the skydiver?

The parachutes all have the same weight. Which will have the largest fall speed when dropped?

Both parachutes will reach the ground at the same time.

The bigger parachute will hit the ground first.

The smaller parachute will hit the ground first.

Two people with the same mass, in parachutes of different surface areas, drop at the same time from a plane and reach terminal velocity. Which will hit the ground first?

It increases the drag force on the skydiver.

It decreases the drag force on the skydiver.

Why does a parachute reduce the terminal velocity of a falling skydiver?

Which two pieces of apparatus could be used to take the measurements needed to find the speed of a falling model parachute?

Which of these forces act on a skydiver as they fall downwards?

When the drag force is larger than the force of gravity.

When the force of gravity is larger than the drag force.

When does a falling object reach a steady speed?

A student measures how long a parachute takes to fall a distance of 2.0 m five separate times. Their readings are 1.5 s , 1.2 s, 1.4 s, 1.3 s and 1.4 s. Calculate the average fall time.

A set of model parachutes with different surface areas were dropped through a distance of 1.5 m. Starting with the fastest, sort the parachutes in order of average fall speed.

A model parachute falls through a distance of 1.8 m in a time of 2.4 s. Calculate the average speed of the parachute during the fall. Give the correct unit.

Starter Quiz

Which two pieces of apparatus could be used to take the measurements needed to find the speed of a falling model parachute?