65.5 kg Frankie...

Question

65.5 kg Frankie is repairing their ship at a dock. He throws a 2.25 kg tool away from him at 3.2 m/s relative to the dock. With what "recoil" speed will he begin to move? 

Answer 1

Let's conserve Frankie's momentum which was initially 0.

So, whatever he does, it will remain as zero so long as on one from outside interferes.

Momentum = mass x velocity

P(before) = P(after)

2.25 x 3.2 = 65.5 x V(frankie)

(There is still a problem that the mass of ship with Frankie should have been given)

V = 0.11 m/s