Newton's Third Law + Terminal Speed (copy)

What is Newton’s Third Law?

Newton’s third law Newton’s third law states that ‘if a body A exerts a force on body B, then body B exerts an equal and opposite force on body A.’

What are the 2 forces acting on a sky diver?

Air resistance upwards and weight downwards

When the sky diver jumps out of the plane, what happens to air resistance and weight?

the air resistance is smaller than the weight this causes the sky diver to accelerate

As they accelerate what happens to the air resitance?

the air resistance increases

When does this continue until?

Air resistance is equal and opposite to the weight.

At this point what happens to their speed?

their speed is constant. this is also known as their terminal speed

What happens when the sky diver opens their parachute?

The forces become unbalanced. the air resistance increases to be larger than the weight. this slows them down

As the sky diver slows down what happens?

the air resistance decreases to become equal to the weight again. this means that a new lower terminal speed is reached

How can terminal speed also be achieved?

Terminal speeds can also be achieved with vehicles travelling horizontally, where air resistance and friction backwards increase to be equal to the engine’s force forward.