Question

A rain drop, with a mass of 2.30 mg falls to the ground. As it is falling, what magnitude of force does it exert on the earth?

Answer 1

Suppose,the rain drop of mass `m` fell from height `H` above the ground,so the velocity with which it hit the ground will be `V=sqrt(2gH)`

Now,suppose,it came to a rest,just after heating the ground in `t s`,so that its final velocity became `0`

So,we can say,change in momentum in this process = `m(0-V)=-mV`

So,rate of change in momentum = `(mV)/t=(msqrt(2gH))/t`

So,this is the force exerted by the rain drop on the earth,now,only value of `m` is given,and that value is enough to interpret how smaller the force will be.