Gravity
GravityGravity 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 opposite direction to that of the object's motion. In the case of a falling object, air resistance pushes up as gravity pulls down, which causes the object to slow down. When Galileo's experiment was repeated on the moon, the hammer and the feather hit the ground at the exact same time. This is due to
the fact that the moon has no atmosphere. Therefore, air resistance doesn't exist on the moon. Also, the amount of air resistance on an object depends on the speed, size, shape, and density of the object. The larger the surface area of the object, the greater the amount of air resistance on it. This is why feathers, leaves, and sheets of paper fall more slowly than pennies, acorns, and crumpled balls of paper.
There is another legend that states that when Newton was lying against a tree in an orchard, he was struck on the head by an apple. He wondered what provided the acceleration for the apple to fall to the ground. Was this a force of the earth on the apple? If so, then the apple must exert a force on the earth according to Newton’s law of action/reaction forces.
Newton applied this theory unto the planets, which orbit the sun. He found by studying astronomical data, that the force that held the earth in orbit around the sun was the same force that drew the apple toward the earth. This was the
force of gravity that is given by this scary formula:
F = Gm1*Gm2
gravity _______
r^2
F equals the force in Newtons, G equals the gravitational constant which is 6.67 * 10^-11 Nm^2 | kg^2, m1 and m2 equal the mass of each body in kilograms, and finally, r equals the distance between the 2 bodies in meters.
If all of this is confusing, I feel your pain, because it took me a long time to get this all down!
Another concept that is important to understand is terminal velocity. Terminal velocity is the highest velocity that will be reached by a falling object. As an object falls...
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