An astronaut with a mass of #90 kg# is floating in space. If the astronaut throws an object with a mass of #5 kg# at a speed of #2/9 m/s#, how much will his speed change by?

1 Answer
Mar 14, 2018

The change in the speed of the astronaut is #=0.012ms^-1#

Explanation:

We have conservation of momentum

#m_1u_1+m_2u_2=m_1v_1+m_2v_2#

The mass of the astronaut is #m_1=90kg#

The mass of the object is #m_2=5kg#

As the astronaut is floating in space initially,

#u_1=u_2=0ms^-1#

The speed of the object is #v_2=2/9ms^-1#

Therefore,

#90v_1+5*2/9=0#

The speed of the astronaut is #v_1=-10/(9*90)=-0.012ms^-1#