A smooth track in the form of a quarter circle of radius 6 m lies in the vertical plane, A particle moves from  $P_1$ to  $P_2$ under the action of forces  ${\overrightarrow{F}}_1,\overrightarrow{F_2}\&\overrightarrow{F_3}$. Force $\overrightarrow{F_1}$  is always towards  $P_2$  and is always 20 N in magnitude. Force $\overrightarrow{F_2}$  is always act horizontally and is always 30 N magnitude, Force $\overrightarrow{F_3}$  always acts tangentially to the track and is of magnitude 15 N.