1. Falling Objects
D. Crowley, 2008

2. Wednesday, April 19, 2017
Falling Objects
To be able to describe the changes in forces on a falling object
Joseph Kittinger – 102’000ft above Earth

3. Forces
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

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

5. Skydiving Stages Complete the skydiving stages worksheet
Label the forces
Draw correctly sized force arrows
Write a sentence explaining the forces experienced by the skydiver during the descent

6. Skydiving Stages
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

7. Skydiving Stages
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)

8. Skydiving Stages
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

9. Skydiving Stages
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)

10. Skydive

11. Directional

12. 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

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