# Gravity is More Than a Name

## Presentation on theme: "Gravity is More Than a Name"— Presentation transcript:

Gravity is More Than a Name

The Funnier Side

gravity - it is the thing which causes objects to fall to Earth.

Gravity gravity is a force which exists between the Earth and the objects which are near it.

Question Are you experiencing a force due to gravity right now?

Follow Up Where could you go to “get away” from gravity?

How and by whom was gravity discovered?
More Questions How and by whom was gravity discovered?

What variables affect the actual value of the force of gravity?

How far-reaching is gravity's influence?

How does gravity affect objects which are far beyond the surface of the Earth?

How can a projectile orbit the Earth?

Doesn't a projectile accelerate towards the Earth under the influence of gravity?

And as such, wouldn't any projectile ultimately fall towards the Earth and ultimately collide with the Earth ?

Free Falling Objects Free-falling objects do not encounter air resistance. All free-falling objects (on Earth) accelerate downwards at a rate of approximately 10 m/s/s

Velocity of an Object in Free Fall

How Far an Object Falls

What is Weightless?

Would an elephant an a feather hit the ground at the same time?

Ok Mr Lovering, but what would really happen?

Astronauts on the orbiting space shuttle are weightless because...
there is no gravity in space and they do not weigh anything. space is a vacuum and there is no gravity in a vacuum. space is a vacuum and there is no air resistance in a vacuum. the astronauts are far from earth's surface at a location where gravitation has a minimal effect.

The Big Misconception "Doesn't a massive object accelerate at a greater rate than a less massive object?".

Falling and Satellite Motion
What does falling have to do with keeping a satellite in orbit?

What if there where no gravity?
Satellite Motion What if there where no gravity?

Falling into the Earth A satellite does fall towards the Earth; only it never falls into the Earth.

The Round Earth

Less than 8000 m/s

Equal to 8000 m/s

Greater than 8000 m/s

Geosynchronous Orbit Perfect for communication satellites

provide true global coverage
Polar Orbit provide true global coverage

How Long Do Satellites Live?
At 300 km altitude it may last for days before it reenters and burns up. At 180 km, this lifetime reduces to mere hours.