Momentum question

Question

A 69.2 kg astronaut is holding a 14.3 kg tool pack while drifting at 17.6 m/s to the right. She throws the tool pack away so that it is drifting at 2.9m/s to the left. How fast is she moving after the throw ? Assume that they are out in deep space with no other forces acting on them.

Answer 1

(69.2 +14.3)*(17.6)= (-2.9)*(14.3) +(69.2)*v

Solve for v and you get 21.84 to the right.

Here we have conservation of momentum. There are no external forces so the momentum before is the same as the momentum after. Hence the statement of equality. On the left side we have the combined mass of the astronaut and the object moving to the right. On the right hand side of the equation we have the object traveling to the left now, so negative, and the astronaut moving with unknown velocity V. Rearrange for V and your Set! Hope this helps!