Question

A coin and a feather are released from the terrace of the school building .which of them will reach the ground first? why?

Answer 1

Heya Friend ☺

I think you had studied Potential energy = mgh
The mass of the coin is more than the mass of the cork that is why the gravitational force acts on the coin is more than the cork that's why coin will reach first


Hope it helps you ☺

Answer 2

According Newton's 2nd equation of motion :

$s = ut + \frac{1}{2} g {t}^{2}$
s = displacement = Height
s is same for both Feather and a Coin as both are release from the same building ( same height )

g = acceleration due to gravity
g acting on both the object is also same which equals to 9.8 m/s^2

u = Initial Velocity = 0 m/s

So we must have
$s = \frac{1}{2} g {t}^{2} \\ 2s = g {t}^{2} \\ g {t}^{2} = 2s \\ {t}^{2} = \frac{2s}{g} \\ t = \sqrt{ \frac{2s}{g} }$

Here s and g for both the objects are same...Above equation is independent of Mass of the objects....Though Feather is much lighter than a Coin but Newtons 2nd equation doesnt depend on their masses as you can see above No mass in the Newton's second equation of motion...

So Time to reach the Coin and Feature will be same or Both the objects will land the graound at the same time according to above equation...

But Due to air resistance Feature experience more resistive force of air in upward direction which we also called Drag...becuase of which it takes more time than Coin to reach the ground...So Coin land the ground earlier than Featther...

If There is no air resistance then both the objects will land at the same time...

Hope it help....