D. Crowley, 2008

 To be able to describe the changes in forces on a falling object Joseph Kittinger – 102’000ft above Earth Tuesday, May 01, 2018

 What are the forces on a skydiver? How do these forces change (think about when they first jump out; during free fall; and when the parachute has opened)  What happens if the skydiver changes their position  The skydiver’s weight (which depends on gravity) remains the same throughout the jump  But their air resistance changes depending upon what they’re doing

 Changing position whilst skydiving causes massive changes in air resistance, dramatically affecting how fast you fall…

For each diagram  Label the forces  Draw correctly sized force arrows  Write a sentence explaining the forces experienced by the skydiver during the descent

Stage 1 – after just jumping from the plane the skydiver is not moving very fast – their weight is a bigger force than their air resistance, so they accelerate downwards

Stage 2 – Eventually the force of the air resistance has increased so much that it is the same size as the skydiver’s weight – the forces are balanced and the speed remains constant (this is terminal velocity)

Stage 3 – When the chute opens air resistance increases dramatically: the air resistance force is much greater than the weight force, so the skydiver slows down

Stage 4 – As the skydiver slows, the air resistance force from the chute is reduced, until it is the same size as the weight force – the forces are balanced and the speed remains constant (this is a new terminal velocity)

 When vehicles and free-falling objects first move they have much more force accelerating them than resistance which is trying to slow them  As speed increases resistance builds up – gradually reducing the acceleration  Eventually the resistance forces is equal to the accelerating force and the object remains at a constant speed (terminal velocity) Apollo 15 parachutes

Velocity Time Speed increases… Terminal velocity reached… Parachute opens – diver slows down New, lower terminal velocity reached Diver hits the ground