SECTION 1 (PART 3) – Falling Objects

AIR RESISTANCE When an object falls, gravity

pulls it down.

Air resistance works opposite of gravity and opposes the motion of objects that move through the air.

AIR RESISTANCE Air resistance causes different

objects to fall with different accelerations and different speeds.

Amount of air resistance depends on the speed, size, and shape of the object.

WHAT IF AIR RESISTANCE DIDN’T EXIST?

This shows a feather and an apple falling in a vacuum.

There is no air resistance in a vacuum so the feather and apple fall with the same acceleration.

Outside of the vacuum, the apple falls much faster due to its mass and shape.

TRUE STORY – CHECK IT OUT!

Feather and Bowling Ball in a Vacuum

TERMINAL VELOCITY As an object falls faster, air

resistance increases.

Eventually the upward air resistance will be equal to the downward force of gravity causing the net force on the object to be zero.

TERMINAL VELOCITY Terminal velocity: highest

speed a falling object will reach

Terminal velocity depends on size, shape, and mass of the falling object.

TERMINAL VELOCITYThe force of air resistance on an open parachute balances the force of gravity.

The parachute opens and the terminal velocity of the sky diver becomes small enough that he/she can land safely.

TERMINAL VELOCITY https://www.youtube.com/watch

?v=p0IZsfzDS4s

BONUS MYTHBUSTERS!

http://www.youtube.com/watch?v=PHxvMLoKRWg