Changing the speed of a parachute | Exit Quiz | Oak National Academy

Match the key words to the explanations.

• gravitational force

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

• drag force

• A device used to increase drag during a fall.

• parachute

• The speed an object falls at.

• resultant force

• A force that pulls objects towards Earth.

• velocity

• A force caused by friction due to air.

Answer explanation

Earth exerts a gravitational force on objects, drag is caused when things move through air, a resultant force takes into account all the forces acting, a parachute slows a person falling by increasing drag and lowering velocity.

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

• 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.

Answer explanation

The gravitational force remains constant but the drag force increases as the speed increases.

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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?

• They stop.

• They slow down.

• They speed up.

• They stay at the same speed.

Answer explanation

There is an overall resultant force of 100 N downwards so the skydiver will be getting faster.

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

• left (smallest)

• center

• right (largest)

Answer explanation

The parachute on the left has the smallest surface area and so has the greatest fall speed.

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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?

• 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.

Answer explanation

The smaller parachute will have less drag and slow down less, so staying at a faster speed (higher terminal velocity) and therefore reach the ground first.

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

• It makes them more streamlined.

• It increases the speed of the skydiver.

• It increases the drag force on the skydiver.

• It reduces the gravitational force.

• It decreases the drag force on the skydiver.

Answer explanation

The parachute provides a high drag force, until it is the same as the gravitational force.