An astronaut with a mass of #90 kg# is floating in space. If the astronaut throws a #20 kg# object at a speed of #6/5 m/s#, how much will his speed change by?

1 Answer
Mar 22, 2018

The change in the speed of the astronaut is #=0.27ms^-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=20kg#

As the astronaut is floating in space initially,

#u_1=u_2=0ms^-1#

The speed of the object is #v_2=6/5ms^-1#

Therefore,

#90v_1+20*6/5=0#

The speed of the astronaut is #v_1=-24/(90)=-0.27ms^-1#