If a curve is drawn expressing the K.E. of a particle as a function of the distance on x-axis.   The slope of this curve represents the instantaneous 

Conceptual    W   =    F.S

Slope : $$\begin{gathered} \Rightarrow \frac{Work}{displacement}=Force---\left(1\right) \\ from work energy theorem , work done =change in KE---\left(2\right) \\ substitute eqn \left(2\right) in \left(1\right) \\ \frac{KE}{displacement}=Force=slope of the curve \\ \frac{k.E}{s}=\frac{m{v}^2}{2s}=ma=Force \because acceleration =\frac{v^2}{2s} \end{gathered}$$