An astronaut with a mass of #85 kg# is floating in space. If the astronaut throws an object with a mass of #18 kg# at a speed of #3/8 m/s#, how much will his speed change by?

1 Answer
Mar 7, 2018

The change in the speed of the astronaut is #=0.079ms^-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=85kg#

The mass of the object is #m_2=18kg#

As the astronaut is floating in space initially,

#u_1=u_2=0ms^-1#

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

Therefore,

#85v_1+3/8*18=0#

The speed of the astronaut is #v_1=-3/8*1/85*18=-0.079ms^-1#