A particle of mass 1kg is moving along x-axis. It’s velocity is $\text{6m/sec}$  at $x=\text{0}$ . Acceleration (a), displacement (x) curve and potential energy(u)-displacement(x) curve of the particle are shown.

$\text{v}-6=24+8$

$\text{v}=38{\text{ms}}^{-1}$

Work done by all the forces $=\Delta \text{KE}$

$\text{w}=\frac{1}{2}\text{m}\left({\text{v}}^{\text{2}}-{\text{u}}^{\text{2}}\right)$

$\text{w}=\frac{1}{2}1\left({38}^2-6^2\right)=\frac{1408}{2}=704\text{J}$

Work done by conservative forces $\Delta \text{U}=-\text{320J}$

Work done by external forces$=\Delta \text{K}-\Delta \text{U}$

$=\text{704}-\text{320}$

$=\text{384}\text{J}$