Answer:
= - M / m v
Explanation:
We must define a system formed by the wagon and the torro, in this case the forces of the movement are internal, so the moment is preserved, write the moment in two moments
Initial. Before the bull's movement, in this case the two are still
p₀ = 0
Final. The bull is moving
= M v + m
p₀ =
0 = M v + m
We cleared the train speed
= - M / m v
The negative sign indicates that the train moves in the opposite direction of the bull