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# Acceleration Due Gravity Essay

Hi George,

From the information given in your question, Newton is the way to go on this.

Near the surface of the Earth, the acceleration due to gravity is ≈ 9.8 m/s2 (that's 9.8 meters per second per second). If you drop an apple from an airplane, skyscraper, or roof of your house, the acceleration due to gravity will always be ≈ 9.8 m/s2.

I respectfully disagree with Vivian:

a) Galileo demonstrated (in his famous Leaning Tower of Pisa experiment in 1589) that heavy and light objects take the same time to fall to the ground. But for the friction effect of air, a feather and a cannon ball would take the same time to fall from the tower.

b) The earth acceleration rate due to gravity is NOT the same universally. Earth's gravity decreases with altitude according to the "inverse square law" - the greater your altitude, the lesser is the earth's gravitational effect.

The inverse square law formula for gravity on earth is: g ≈ 9.8 (4000/(4000+h))2. where "h" is the altitude (in miles) above the surface of the earth (radius about 4,000 mi). Here are some examples:

• In an airplane at 30,000 feet (5.7 miles), g ≈ 9.77 m/s2 (almost identical to surface of earth).
• At about 235 miles (altitude of ISS satellite), g ≈ 8.74 m/s2.
• At about 1,000 miles (inner space), g ≈ 6.3 m/s2.
• At about 125,000 miles (half way to the moon), g ≈ 0.01 m/s2.

High school physics classes will never ask you about relativity, accounting for air friction, or high altitudes.

Don't over-engineer the problem and worry about all those vectors vectors.

bob

## Gravity Essay

1263 Words6 Pages

Gravity is really an unknown force. We can define it as a field of influence, and that it effects the entire existence of the universe. Some people think that gravity consists of particles called gravitons, which travel at the speed of light. The only thing we do know is how gravity operates in different parts of our universe.
Without gravity, there would be no space and time.

There is a legend that says that Galileo once dropped two objects off the Leaning
Tower of Pisa to show that the heavier of the two objects

dropped faster. If a feather and hammer were the two objects he used then obviously the hammer would hit the ground first. This is due to air resistance, which is the force air exerts on a moving object. This force acts in the…show more content…

Terminal velocity is the highest velocity that will be reached by a falling object. As an object falls through air, air resistance gradually increases until it balances the pull of gravity. According to the law of inertia, when the forces acting on an object are balanced, the motion of the object will not change. When this happens, the falling object will stop accelerating. It will continue to fall, but at a constant, final velocity. Newton's laws of motion and law of gravitation can be used to explain the forces, position and motion of all objects in the universe. A simple

analogy of how gravity controls the motion of a planet around the Sun can be shown by a mass on the end of a string being spun around in a horizontal

plane at constant speed. The ball has constant speed but the direction is always changing so according to the definition of velocity the object must be undergoing a constant acceleration. According to
Newton’s second law, for a mass to be accelerating, it must have a resulting force acting upon it. The question is: Where does this force come?

The forces involved can be examined by considering what happens when the string breaks. When the string breaks the mass is no longer constrained to travel in its circular orbit and moved off in the direction as shown. This indicates that there must be a force holding the mass in its circular orbit.
It is directed towards the center of the circle and is called

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