Physics
posted by Elizabeth .
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 92.5 kg. The mass of the rock is 0.310 kg. Initially the wagon is rolling forward at a speed of 0.550 m/s. Then the person throws the rock with a speed of 17.0 m/s. Both speeds are relative to the ground. Find the speed of the wagon after the rock is thrown directly forward.
Answer in m/s.
Find the speed of the wagon after the rock is thrown directly backward.
Answer in m/s.

m1+m2+m3 = 92.5 kg.
m1= 0.31 kg
m2+m3 =92.19 kg
v=0.55 m/s
v1=  17 m/s
v2=?
(m1+m2+m3) •v=  m1•v1+(m2+m3) •v2
v2= {(m1+m2+m3) •v +m1•v1}/(m2+m3)=…