posted by Jordan .
A wagon is rolling forward on level ground. Friction is negligible. The person sitting in the wagon is holding a rock. The total mass of the wagon, rider, and rock is 96.5 kg. The mass of the rock is 0.250 kg. Initially the wagon is rolling forward at a speed of 0.460 m/s. Then the person throws the rock with a speed of 16.5 m/s. Both speeds are relative to the ground. Find the speed of the wagon after the rock is thrown directly forward.
Find the speed of the wagon after the rock is thrown directly backward. ____m/s
Apply the rule that the total momentum remains the same.
They should have made it clear if the 16.5 rock velocity is with repect to the ground or the wagon. It probably should be with respect to the wagon.Whichever you assume will make a small difference in the answer.
I hope that is enough information for you to work the problem yourself.
I don't have time to answer everyone's physics questions here and will be helping mainly students who show their own work.