If the force acting on a body is inversely proportional to its speed, then its kinetic energy is 

Options

A. linearly related to time
B. inversely proportional to time
C. inversely proportional to the square of time
D. a constant

Answer

A

Explanation

`F prop 1/v " or " F = C/v`
where C is the constant of proportionality.
`:. ma = C/v " or " m (dv)/(dt) = C/v " or " vdv = (Cdt)/(m)`
Integrating both sides , we get `(v^2)/v = (Ct)/m " or " 1/2 mv^2 = Ct`
Kinetic energy, `K = 1/2 mv^2 = Ct or K prop t`