An object is thrown upward from the top of a 160-foot building with an initial velocity of 144 feet per second. The height, h, of the object after t seconds is given by the equation h=-16t^2+144t+160. When will the object hit the ground?

Question

An object is thrown upward from the top of a 160-foot building with an initial velocity of 144 feet per second.  The height, h, of the object after t seconds is given by the equation h=-16t^2+144t+160.  When will the object hit the ground?

The object will hit the ground when the time is _____ seconds.

Reiny · Answer

when it hits the ground, h = 0 so solve: -16t^2 + 144t + 160 = 0 divide each term by -16 t^2 - 9t - 10 = 0 easy to solve, use factoring.