A 0.010kg bullet is fired straight up at a falling wooden block that has a mass of 2.0kg. The bullet has a speed of 750m/swhen it strikes the block. The block originally was dropped from rest from the top of a building and had been falling for atime t when the collision with the bullet occurs. As a result of the collision, the block with the bullet in it reverses direction, rises and comes to a momentary halt at the top of the building. Find the time t.