An astronaut with a mass of #80 kg# is floating in space. If the astronaut throws an object with a mass of #11 kg# at a speed of #3/8 m/s#, how much will his speed change by?

1 Answer
Jul 12, 2017

The change in speed of the astronaut is #=0.051ms^-1#

Explanation:

If the astronaut is floating in space, his speed is #u_1=0ms^-1#

We have conservation of momentum

#m_1u_1=m_1v_1+m_2v_2#

The final speed of the astronaut is #=v_1#

The mass of the astronaut is #m_1=80kg#

The mass of the object is #m_2=11kg#

The final speed of the object is #v_2=3/8ms^-1#

Therefore,

#80*0=80*v_1+11*3/8#

#v_1=-11/80*3/8=-0.051ms^-1#