Comparing the speeds of different parachutes | Starter Quiz | Oak National Academy

Which force causes objects to fall to the ground?

• friction

• electromagnetic

• gravitational

• tension

Answer explanation

The gravitational force of Earth will pull objects downwards.

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

• Forces have magnitude (size).

• Forces have direction.

• Forces have both magnitude (size) and direction.

• The colour of the arrow indicates the type of force.

Answer explanation

Forces are shown as arrows because they have both direction and magnitude (size).

Which force opposes movement through liquids?

• gravitational

• tension

• drag

• magnetic

• reaction

Answer explanation

Drag forces, like air resistance or water resistance, oppose movement through fluids (liquids and gases).

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

• 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.

Answer explanation

The parachute is used to increase the drag force and slow the car down as quickly as possible.

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?

• 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 slow down.

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

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

Answer explanation

The force will cause a change in speed (speeding up) for the full 30 s as it acts all the time.

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

• It starts moving upwards.

• It immediately changes to a new constant speed.

• It gradually slows down.

• It stops moving immediately.

• There is no change in the movement.

Answer explanation

The parachute increases the drag and this slows the box down. It does not stop until it reaches the ground.