Question

An astronaut with a mass of `80 kg` is floating in space. If the astronaut throws a `12 kg` object at a speed of `6 m/s`, how much will his speed change by?

Answer 1

I found `0.9m/s` in the opposite direction of the object.

Explanation:

We can use Conservation of Linear Momentum `p=mv` along the horizontal `x` direction so that:

`p_("before")=p_("after")`

`(80*0)+(12*0)=(80*v)+(12*6)`

`0=80v+72`

`v=-72/80=-0.9m/s` opposite to the object