GRAVITYGRAVITYWHY THINGS FALLWHY THINGS FALL

Believed that heavier objects fall faster than lighter ones.

aristotle - aristotle - (384-322 B.C.)(384-322 B.C.)

GALILEO - GALILEO - (1564-1642)(1564-1642) Believed that ALL objects fall at the same rate. (in the absence of air resistance)

This is called FREE FALL

Galileo used INCLINED PLANES to show this.

US ASTRONAUT - DAVID SCOTTApollo 15 Lunar Mission

- August 1971-

isaac newtonisaac newton - (1642-1727) - (1642-1727)

Watched apples falling from trees and noticed they ALWAYS fell toward center of Earth - never sideways.

Reasoned if gravity acts on the tops of trees and the tops of mountains, maybe it went all the way to the MOON!

Every particle is attracted to every other particle.

This force (GRAVITY) is based on MASS and DISTANCE.

F = GF = Gmm mm11 22

rr 22

The larger the mass of the two objects, the greater the gravitational force.

The greater the distance between the two objects, the lower the gravitational force.

If you double the mass, you double the force.

If you double the distance, you reduce the force by four times.

GRAVITATIONAL LAWGRAVITATIONAL LAW GRAVITATIONAL LAWGRAVITATIONAL LAW

Which has greater gravity?

A

B

C.

D.

Which has greater gravity?

albert einstein - (1879-1955) albert einstein - (1879-1955)

Gravity is a distortion of SPACE & TIME, caused by the local presence of MASS & ENERGY.

Space is CURVED by gravity.

The more mass, the greater the curvature.

With enough mass (star), the curve would become so great NOTHING COULD ESCAPE - NOT EVEN LIGHT.

Gravity Bends LightGravity Bends Light

http://www.youtube.com/watch?v=AzecHW-DTqY

BLACK HOLES BLACK HOLES