Can you please answer this for me? Been working on it for so long.

Question

A water-balloon launcher with a mass of 1.75 kg is suspended on a wire. It fires a 1.25 kg balloon to the east at a velocity of 12.0 m/s. What is the resulting velocity of the launcher if the net force on the launcher is equal to the reaction force?

A. 6.1 m/s east

B. 16.8 m/s west

C. 7.6 m/s west

D.8.6 m/s west

Answer 1

D.

Use conservation of momentum.

Assume positive direction to east, negative to west

At start, m = 1.75 + 1.25 = 3 kg, v = 0. momentum = mv = 0

At finish, if v is velocity of launcher 1.25 x 12 + 1.75 v = 0 (total momentum must be zero)

giving v = - 8.57 m/s (in other words 8.57 m/s to the west)