Question

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

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

Answer 1

Answer: (A)

linearly related to time

Answer 2

Given, force $(F)\propto \frac{1}{v}$
or $ma=\frac{k}{v}$
or $m\times \frac{v}{t}=\frac{k}{v}$
or $mv^{2}=kt$
or $\frac{1}{2}mv^{2}=k't$
$\Rightarrow$ $KE\propto t$