A particle of mass m, initially at rest, is acted upon by a variable force F for a brief interval of time T. It begins to move with a velocity u after the force stops acting. F is shown in the graph as a function of time. The curve is a semicircle.

• A.                                 \[u=\frac{\pi F_{0}^{2}}{2m}\]                
• B.                                    \[u=\frac{\pi {{T}^{2}}}{8m}\]                
• C.                                 \[u=\frac{\pi {{F}_{0}}T}{4m}\]                
• D.                                    \[u=\frac{{{F}_{0}}T}{2m}\]