Explanation:
Well first let's find the derivative in using the power rule
h'(t) = (-4.9)t + 157
h'(t) = -9.8t + 157
we can see from the image above that the maximum height is 1452.602 so that is the answer to the second question.
h'(1452.602) = -9.8(1452.602) + 157
h' = 14,078.500