feather and coin experiment. explain.
 

In a famous demonstration, Galileo supposedly dropped a heavy weight and a light weight from the top of the Leaning Tower of Pisa to show that both weights fall at the same acceleration. However, this rule is true only if there is no air resistance. This experiment lets you repeat Galileo's experiment in a vacuum.

The free fall of a coin and feather are compared, first in a tube full of air and then in a vacuum. With air resistance, the feathers fall more slowly. In a vacuum, the objects fall at the same rate independent of their respective masses. That means coin and feather both reach ground at same time in a vacuum.

Larger objects experience more air resistance than smaller objects. Also, the faster an object falls, the more air resistance it encounters. When the retarding force of the air just balances the downward pull of gravity, the object will no longer gain speed; it will have reached what is called its terminal velocity.

Since the feather is so much lighter than the coin, the air resistance on it very quickly builds up to equal the pull of gravity. After that, the feather gains no more speed, but just drifts slowly downward. The heavier coin, meanwhile, must fall much longer before it gathers enough speed so that air resistance will balance the gravitational force on it. The coin quickly pulls away from the feather.

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