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

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

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

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

Comparing the speeds of different parachutes

Science

Calculating speed

Measuring speed: practical

Measuring speed accurately

Reading distance-time graphs

Interpreting distance-time graphs

Changing speed

Newton's First Law

Streamlining

Changing the speed of a parachute

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 opposes movement through gases and liquids.

A device used to slow fast objects, using drag forces.

The force pulling an object downwards to Earth.

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

Match the key words to their explanations.

When the gravitational force is less than the drag force.

When the gravitational force is greater than the drag force.

When the gravitational force is equal and opposite to the drag force.

When does a falling object reach a steady top speed?

The parachutes will all have the same fall speed.

The parachute with the greatest surface area will have the greatest fall speed.

The parachute with the smallest surface area will have the greatest fall speed.

The parachute with the middle surface area will have the greatest fall speed.

During a test. a pupil drops paper parachutes with different surface areas but equal weights. Which is the correct prediction about the fall speed?

In a parachute drop test the times recorded are 1.21 s, 1.24 s, 1.23 s and 1.28 s. What is the mean time?

The gravitational force increases and the drag force increases.

The gravitational force increases and the drag force decreases.

The gravitational force stays the same and the drag force decreases.

The gravitational force stays the same and the drag force increases.

The gravitational force stays the same and the drag force stays the same.

A skydiver is falling with their parachute closed. What happens to the size of the forces on them immediately after opening the parachute?

A parachute is tested five times, falling through 1.5 m. The times are: 0.80 s, 0.70 s, 0.72 s, 0.77 s and 0.76 s. Calculate the average fall speed.

Which force causes objects to fall to the ground?

Forces have both magnitude (size) and direction.

The colour of the arrow indicates the type of force.

Why is a force represented by an arrow on a diagram? Choose the best answer.

Which force opposes movement through liquids?

The drag force increases and this slows the car down.

The drag force decreases and this slows the car down.

The driving force increases and this slows the car down.

The driving force decreases and this slows the car down.

At the end of a race a car opens a parachute. Why do they do this?

The car will stay at the same speed for the 30 s.

The car will quickly speed up and then move at a steady speed for 30 s.

The car will continue to speed up throughout the 30 s.

The car will speed up and slow down throughout the 30 s.

A car moving along a flat road has an unbalanced forwards force acting on it for 30 s. What will happen to the car's movement?

It immediately changes to a new constant speed.

An emergency food parcel is dropped from a plane. Near the ground the parachute opens. What happens to the movement of the food parcel?

Starter Quiz

Which force causes objects to fall to the ground?