An object propelled vertically upward with an initial velocity of 84 feet per second. The height h (in feet) of the object after t seconds is the given by h(t)= -16t^2 + 76t. After how many seconds wi

An object propelled vertically upward with an initial velocity of 84 feet per second. The height h (in feet) of the object after t seconds is the given by h(t)= -16t^2 + 76t. After how many seconds will the object strike the ground?