a car is travelling on a straight road with velocity 55 ft/sec at time t=0. for 0 < or equal to t < or equal to 18 seconds, the car's acceleration a(t),t/sec^2, is the piecewise linear function defined by the graph above.

(a) Is the velocity of the car increasing at t=2 seconds? why or why not?
(b) At what time in the interval, other than t=0, is the velocity of the car 55 ft/sec? why?
(c) on the time interval, what is the car's absolute maximum velocity, in ft/sec, and at what time does it occur?
(d) at what times in the interval, if any, is the car's velocity equal to 0?