WeyPhys KS3 Forces & gravity

Which direction does a friction force act?

• Left

• Right

• Downwards

• Always against the motion or pulling force

Which force acts upwards on an object immersed in a fluid?

• Flotation force

• Water resistance

• Anti-gravity

• Upthrust

The end of object attracts to both poles of a magnet. What is the object?

• Another magnet

• A piece of copper

• A piece of glass

• A piece of iron

If a person pushes a large stationary crate with a force of 250N to the left, but the friction force is 250N to the right...

• The forces are balanced and the crate will stay still

• The forces add up to 500N so the crate will accelerate

• The forces add up to 500N so the crate stands still

• The forces are unbalanced so the crate stays still

A cyclist is riding on level ground with a forwards force of 40N. The air-resistance pushing against her is also 40N.

She...

• ...has a resultant force of 0N so she stops

• ...has a resultant force of 0N and carries on at the same speed

• ...has a resultant force of 80N so she accelerates

• ...has a resultant force of 80N so she decelerates

A car has a forwards driving force of 1200N and air-resistance and friction forces pushing backwards of 500N.

The car will...

• Accelerate because the forces are unbalanced and there is a forwards resultant force of 700N

• Accelerate because the forces are balanced, with a forwards resultant force of 1700N

• Carry on at the same speed

• Decelerate

Why are swimmers top speeds lower than runners?

• Water is less dense than air and has less resistive force at the same speed.

• Water is more dense than air and has more resistive force at the same speed

• Water resistance acts upwards

• Water resistance is due to particles

When an object falls, it accelerates at first because...

• ...the air-resistance is greater than its weight

• ...the air-resistance is equal to its weight

• ...the air-resistance is smaller than its weight

• ...the forces on it are balanced

What force keeps planets orbiting the Sun?

• Magnetism

• Electrostatic

• Gravity

• The strong nuclear force

Gravity is a force which...

• ...only attracts very large objects together

• ...attracts any objects which have an electric charge

• ...attracts any objects which have mass

• ...both attracts and repels objects