A ball is thrown upward with an initial velocity of 48 ft/sec from a height 640ft. It's height h, in feet, after t seconds is given by h(t)= -16t^2 +48t+640. After how long will the ball reach the ground?
The ball will reach the ground in ___seconds
We equate h(t) to 0 to find the time at which the ball reaches the ground. 16t² - 48t - 640 = 0 t² - 3t - 40 = 0 t = 8, t = -5 Time cannot be negative so second value neglected. The ball will reach the ground in 8 seconds.
