Two people are standing on a 2.19-m-long platform, one at each end. The platform floats parallel to the ground on a cushion of air, like a hovercraft. The two people, the platform and a 3.30-kg ball are all initially at rest. One person throws the 3.30-kg ball to the other, who catches it. The ball travels nearly horizontally. Excluding the ball, the total mass of the platform and people is 185 kg. Because of the throw, this 185-kg mass recoils. How far does the platform move before coming to rest again?