A particle moving along X-axis has acceleration ‘f’ at time ‘t’ given by $\mathrm{f}={\mathrm{f}}_0\left(1-\frac{\mathrm{t}}{\mathrm{T}}\right)$ where ${\mathrm{f}}_0$, T are constants. The particle at t = 0 has zero velocity. In the time interval between t = 0 and the instant when f = 0, the particle velocity ${\mathrm{v}}_0$ is