An aircraft dropped a box of emergency supplies to a group of trampers. The height of the box above the ground, h, at time, t is given by the formula; h = 520 - 5t^2, where h is in metres and t is in seconds.
Find how long it takes for the box to fall to the ground.
520 - 5 t ^ 2 = 0
520 = 5 t ^ 2 Divide both sides by 5
104 = t ^ 2
t = sqrt ( 104 ) = 10. 198 sec