An astronaut with a mass of #80 kg# is floating in space. If the astronaut throws an object with a mass of #12 kg# at a speed of #2 m/s#, how much will his speed change by? Physics Momentum and Collisions Conservation of Momentum 1 Answer ali ergin Jun 3, 2016 #v_a^'=-0.3" "m/s# Explanation: #"Total momentum before event is zero"# #m_a=80" "kg" ; "v_a=0# #m_o=12" "kg" ; "v_o=2" "m/s# #P_b=m_a*v_a+m_o*v_o# #P_b=80*0+12*0=0# #"Total momentum after is :"# #P_a=m_a*v_a^'+m_o*v_o^'# #P_a=80*v_a^'+12*2# #P_a=80*v_a^'+24# #P_b=P_a" momentum is conserved "# #0=80*v_a^'+24# #80*v_a^'=-24# #v_a^'=-24/80=3/10=-0.3# #v_a^'=-0.3" "m/s# Answer link Related questions Why does Newton's cradle stop? How does the conservation of momentum apply in rotational motion? How does the conservation of angular momentum effect the stability of a bike? What is the law of conservation of momentum? What is conservation of angular momentum? What is an inelastic collision? What are some examples of an elastic collision? What is an elastic collision? What is the conservation of momentum? A fly splats on your windshield. What is the collision type? See all questions in Conservation of Momentum Impact of this question 1759 views around the world You can reuse this answer Creative Commons License