A particle released from rest is falling through a thick fluid under gravity. The fluid exerts a resistive force on the particle proportional to the square of its speed. Which one of the following graphs best depicts the variation of its speed v with time t –

Options

A.
B.
C.
D.

Answer

A

Explanation

Let ball is moving with speed v at anytime t.
Hence, `m(dv)/(dt)=mg-kv^2`
On the basis of equation we can say that speed first increases and become constant when `mg = kv^2`