A ball is thrown straight up such that its height, in feet, above the ground after t seconds is H(t)=53⋅t−16t^2. Find the time t when the ball is traveling downward at 13.25 ft/s

Question

A ball is thrown straight up such that its height, in feet, above the ground after t seconds is H(t)=53⋅t−16t^2.

Find the time t when the ball is traveling downward at 13.25 ft/s

Answer 1

h(t) = -16t^2 +53t

v(t) = -32t +53= 13.25

t = (53-13.25)/32

= 39.75/32 = about 1.24 = about 1 1/4 seconds at 13.25 feet per second