Vanessa throws a tennis ball in the air. The function h(t)=-16t^2+45t+7 represents the distance, in feet, that the ball is form the grounf at any time t. At what time, to the nearest tenth of a second, is the ball at its maximum height?

2 answers

If the function h(t)= +45t -16t^2 +7 represents the distance, in feet, that the ball is form the ground at any time,the ball is thrown upward with a velocity of 45fps from a height of 7 feet above the ground.

The final zero velocity of zero is reached from Vf = Vo - gt or 0 = 45 - 32t making the maximum height time 1.406 seconds or 1.4 seconds.

Alternatively, taking the first derivitive of h = Vot - (gt^2)/2 or dh/dt = 45t - 32t = 0 making t = 1.4 sec.
the answer is 2.86 when rounded to the nearest hundred