Question

An astronaut with a mass of `90 kg` is floating in space. If the astronaut throws an object with a mass of `3 kg` at a speed of `2 m/s`, how much will his speed change by?

Answer 1

Data:-
Mass of astronaut`=m_1=90kg`
Mass of object`=m_2=3kg`
Velocity of object `=v_2=2m/s`

Velocity of astronaut`=v_1=??`

Sol:-

Momentum of the astronaut should be equal to the momentum of object.

Momentum of astronaut=Momentum of object
`implies m_1v_1=m_2v_2`

`implies v_1=(m_2v_2)/m_1`

`implies v_1=(3*2)/90=6/90=2/30=0.067 m/s`

`implies v_1=0.067m/s`