Question: A hot-air balloon rises vertically from the ground so that its height after t sec is h = ½t2 + ½t ft (0 ≤ t ≤ 60).
a. What is the height of the balloon at the end of 40 sec?
b. What is the average velocity of the balloon between t 0 and t= 40?
c. What is the velocity of the balloon at the end of 40 sec?