Baseline (Aiming for 4): Describe the forces acting on object falling through a fluid. Further (Aiming for 6): Describe the changes in forces acting on an object which results in it accelerating and then reaching a terminal velocity. Challenge (Aiming for 8): Explain the motion of an object falling through a fluid by considering the forces acting through all phases of motion.

A Long Way down… Felix Baumgartner broke several world records on Oct 14th 2012, by skydiving from an amazing height of 39,000 metres (24 miles). He was falling for a total time of 9 minutes and 3 seconds.

Faster than the speed of sound While Felix was falling he reached a maximum speed of 833.9mph. The speed of sound is 768 mph at sea level. The means that Felix managed to travel faster than the speed of sound. He is the first skydiver to ever do this.

The Previous Record Joe Kittinger previously held the record for the highest skydiver. He jumped from 19.5 miles… in 1960! Joe helped Felix in his record skydive, and was the only person that Felix was talking to throughout his dive.

Terminal velocity What is terminal velocity? What factors affect terminal velocity? How can we calculate terminal velocity?

Terminal velocity When an object is dropped, we can identify three stages before it hits the ground: At the start, the object accelerates downwards because of its weight. There is no water resistance. There is a resultant force acting downwards. Draw these forces on your plasticine.

Terminal velocity When an object is dropped, we can identify three stages before it hits the ground: As it gains speed, the object’s weight stays the same, but the water resistance on it increases. There is a resultant force acting downwards. Draw these forces on your plasticine.

Terminal velocity When an object is dropped, we can identify three stages before it hits the ground: Eventually, the object’s weight is balanced by the water resistance. There is no resultant force and the object reaches a steady speed, called the terminal velocity. Draw these forces on your plasticine.

What could Felix do to change his terminal velocity? Air Resistance Gravity

Why has no one gone this fast before? Air Resistance Gravity

Terminal velocity v/t graph Less acceleration as air resistance increases