A wagon is rolling forward on level ground where friction is negligible. The person sitting in the wagon is holding a rock (m= 0.300 kg). The total mass of the wagon, person, and rock is 95.0 kg. Initially the wagon is rolling forward at a speed pf m/s. The person throws the rock with a speed of m/s. Both speeds are relative to the ground. Discover the speed of the wagon after the rock is thrown forward in one case and backward in another.