An astronaut with a mass of #110 kg# is floating in space. If the astronaut throws a #3 kg# object at a speed of #3 m/s#, how much will his speed change by?

1 Answer
Dec 29, 2017

The change in speed of the astronaut is #=-0.82ms^-1#

Explanation:

We have conservation of momentum

#m_au_a+m_ou_o=m_av_a+m_ov_o#

The initial speeds of the object and the astronaut are #=0#

#u_a=u_o=0ms^-1#

The mass of the object is #m_o=3kg#

The speed of the object is #v_o=3ms^-1#

The mass of the astronaut is #=110kg#

Therefore,

#110*v_a+3*3=0#

#v_a=-9/110=-0.082ms^-2#

The negative sign indicates that the astronaut will move in the opposite direction of the object.