A ball is thrown from an initial height of 7 feet with an in

A ball is thrown from an initial height of 7 feet with an initial upward velocity of 27 ft/s. The ball\'s height h (in feet) after t seconds is given by the following. h = 7 + 27t - 16t^2 Find all values of t for which the ball\'s height is 17 feet. Round your answer(s) to the nearest hundredth. (If there is more than one answer, use the\"or\" button.)

Solution

h = 7 + 27t - 16t^2

find t when h = 17 feet

So, 17 = 7 +27t -16t^2

-16t^2 +27t -10 =0

solve the quadratic equation :

t = [ -27 +/- sqrt(27^2 - 4*10*16) )/-32

t = 0.5489 ; t =1.138

So, t = 0.55 sec ; t = 1.14 sec (there will be two times at which height is 17ft)