Can a body have zero velocity, still accelerating?

Acceleration is the time rate of change of velocity. Give an example of a body possessing zero velocity and still accelerating.

Can a body have constant velocity and still have a varying speed?

If s=2t^(3)-6t^(2)+a t+5 is the distance travelled by a particle at time t and if the velocity is -3 when its acceleration is zero, then the value of a is

A body having an initial velocity V_0 has an acceleration a. Using velocity-time graph derive an equation for displacement of the above body.