Gravity

LAW OF UNIVERSAL GRAVITATION

•Universal Law of Gravitation – all objects in the universe attract each other by the force of gravity.

•The size of the force depends on the mass of the objects and the distance between them.

With no air resistance why do the elephant and mouse fall together?

•FALLING OBJECTS•The acceleration of a falling object is due to the force of gravity between the object and the earth.•Near the surface of the earth gravity is equal to

9.8 m / sec2.

Look at the forces

Regardless of mass, acceleration due to gravity is always the same on Earth.

9.8 m/s2

Every second an object falls it’s velocity increases by 9.8 m/s

NO AIR RESISTANCE

AIR RESISTANCE•Air resistance opposes the downward motion of falling objects (fluid friction).•As an object falls, the air resistance gradually becomes equal to the pull of gravity.•When this occurs the forces are balanced.•There can be no more acceleration and the object falls at a constant velocity.•This is called the terminal velocity.

As an object falls with air resistance the force of air increases as the object increases speed.

WHEN BALANCED = TERMINAL VELOCITY