If the box is a distance 1.81 m from the rear of the truck when the truck starts, how much time elapses before the box falls off the truck?

If the box is a distance 1.81 m from the rear of the truck when the truck starts, ... Force of Friction = mu_s * Normal Force (M * G) ... The box starts moving! ... Now that the box is moving, the bed of the truck pulls at it with 17.4 ... out how long it will take the box to reach the back of the truck ... T^2 = 2 * 1.81 /.64