The velocity time graph shows the movement of a particle alobg a straight line. The particle passes a point, A, when t=0. It maontains a constant spee, u ms -1, for T seconds and then decelerates uniformly before coming to rest at B. If the average speed for the qhole movement is 40 ms, calculate the valie of u. Given that the deceleration betweeen T second and 4T second is 5 ms calculate the value of T.