The position, velocity and acceleration functions are all related in that:

Velocity is the derivative of the position function, and acceleration is the derivative of the velocity function, and the second derivative of the position function.

Therefore if the position function is defined as (taking as a constant):

A.

B.

C. For this problem, understand that for an object to be at rest, its velocity must be equal to 0. Therefore solve the equation given in A for 0:

For what value(s) of t, between 0 and 3 will make the above equation 1?

D. You have your velocity function - now you are being asked for what values of t will you have maximum velocity. In others words, optimize the velocity function.