An astronaut with a mass of #75 kg# is floating in space. If the astronaut throws an object with a mass of #2 kg# at a speed of #5/4 m/s#, how much will his speed change by?

1 Answer
Mar 4, 2018

The speed of the astronaut will change by #=1/30ms^-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=75kg#

The mass of the object is #m_2=2kg#

As the astronaut is floating in space initially,

#u_1=u_2=0ms^-1#

The speed of the object is #v_2=5/4ms^-1#

Therefore,

#75v_1+5/4*2=0#

The speed of the astronaut is #v_1=-5/4*1/75*2=-1/30ms^-1#