A firework mortar is launched straight upward from a pool deck platform 3 m off the ground at an initial velocity of 42 m/sec the height of the mortar can be modeled by h(t)= -4.9t^2 + 42t + 3 where h(t) is the height in meters and t is the time in seconds after launch.
a. Determine the time at which the mortar is at its maximum height. Round to 2 decimal places.
b. What is the maximum height? Round to the nearest meter.