# A body is acted upon by force which is inversely proportional to the distance covered. The work done will be proportional to:

a) s

b) s2

c) √s

d) none of the above

Answer: d) none of the above

Solution:

F ∝ (1/s)

⇒ F = k/s

$$\begin{array}{l}W = \int_{s_{1}}^{s}F.ds\end{array}$$

$$\begin{array}{l}W = \int_{s_{1}}^{s}\frac{k}{s}.ds\end{array}$$

= kIn(s/s1)