Teacher Azizah conducted an experiment to determine the velocity of the trolley along a straight track. The velocity, v cms[sup]-1[/sup], of the trolley after passing the fixed point O is given by [math]v=t^2-7t+6[/math]. [br][Assume the movement to the right is positive][br]Find
(a) the initial velocity, in cms[sup]-1[/sup], of the trolley,
(b) the range of time, in seconds, when the trolley is moving to the left,[br]
(c) the range of time, in seconds, when the acceleration of the trolley is positive.[br]
[math]t>\frac{7}{2}[/math]