Gravity and Free Fall

Usually, when we think of gravity, we think of the apple falling on Newton's head. This is probably a myth, although Newton may have observed a falling apple and thought of gravity. Newton could tell you what gravity did, but he could never quite explain what it was. Gravity influences how fast an object will fall. Every object on Earth falls at 9.81 meters/second² not taking into account air resistance. Information for this article was obtained from Gravitation from Wikipedia the free encyclopedia.

Einstein described gravity as a curvature in space. He envisioned the Sun causing an indentation in space, like dropping a weight on a pillow, causing an indentation in the pillow. He, also, saw the Earth rolling along this curvature around the sun.

We know that if an object has enough mass its gravity will cause it to have a spherical shape, like the planets. Any two masses have gravitational influence on each other. In fact, you have gravitational influence on any object around you. The gravity is so small, that it's unnoticeable. Only when you get to the enormous masses of planets, then gravity becomes important.

Gravity is a force that acts on your body by another mass. A force is a push or pull. Gravity is a force that always pulls and never pushes. The Earth pulls you to its center generating the feeling of weight. The Moon pulls you less, because the Moon has less mass. So gravity is a function of mass. Your weight is equal to your mass times the acceleration of gravity on Earth.The acceleration of gravity of an object is just the amount an object will change speed over a specific time interval in a free fall. If you were on another planet, then your weight would be equal to your mass times the acceleration of gravity on that planet. Since Mars, has less mass than the Earth, then you would weigh less on Mars. In fact, mountain ranges on Mars climb higher than on Earth because of the decreased effect of gravity.

Objects on Earth fall at the rate of 9.81 meters/second every second. So, an object falling for 1 second would reach a speed of 9.81 meters/second. An object falling for two seconds would reach a speed of 9.81 times 2 which is equal to 19.6 meters/second.

If you were to throw an object upward with a velocity of 60.0 meters/second, then it would take 6.12 seconds to reach the top of its path. The object would decelerate at 9.81 meters/second² until it reached a velocity of zero.So, for each second it travels upward it slows down by 9.81 meters/second in the absence of air resistance. Dividing 60.0 by 9.81 is 6.12. I takes 6.12 seconds for its velocity to reach zero.

It spends an equal amount of time moving down as it does moving upward. It takes another 6.12 seconds to travel back to your hand. It gains speed moving down. It accelerates downward at 9.81 meters/second². It gains 9.81 meters/second of speed for each second of falling. So, falling for 6.12 seconds downward; it will reach a speed of 60.0 meters/second. Multiplying 9.81 x 6.12 equals 60.0. The final speed of the ball is 60 meters/second ; the same as the initial speed.The ball spends a total of 12.14 seconds in the air. Remember, we are assuming no air resistance in these calculations.

Gravity exists wherever there is mass. Gravity is everywhere. No one can tell you with certainty, what it is. But we do know that it is an attraction between objects. We also know that all objects fall at 9.81 meters/second² not taking into account air resistance.

Gravitation from Wikipedia the free encyclopedia, Wikipedia