Page 88 - Force 10

➢ When a feather and coin are dropped towards the surface of the earth, do they reach the ground

together? If the experiment is done in the moon, what difference occurs? Write with reason.

When a feather and coin are dropped towards the surface of the earth, they do not reach the ground

together at the same time due to effect of air resistance. It is because the effect of air resistance is

more in the feather than that of coin since feather have large surface area and get more upthrust

applied by air resistance but the surface area of coin is smaller, thus gets lesser air resistance.

If the experiment is done in the moon, both the coin and feather will reach the ground together

at the same time. It is because the moon does not have atmosphere so due to lack of atmosphere(

air resistance), every falling objects fall freely on the moon’s surface with the acceleration equal to

acceleration due to gravity of the moon.

➢ Why does a sheet of paper fall later on the earth surface than the paper ball equal weight dropped

from a certain height?

The magnitude of air resistance depends on the surface area and shape of the falling bodies i.e.. the

larger the surface area of the falling body, the higher will be the air resistance and vice-versa. The

sheet of paper have larger surface area and get more air resistance but the paper ball have lesser

surface area and thus get lesser air resistance. So, though the masses are the same, paper ball due to

lesser surface area gets lesser air resistance and falls faster than a sheet of paper.