Question

An astronaut with a mass of `80 kg` is floating in space. If the astronaut throws an object with a mass of `7 kg` at a speed of `3/8 m/s`, how much will his speed change by?

Answer 1

`v_a=-0,0328 m/s`

Explanation:

`P_b:P_a+P_o`
`P_b:"the sum of momentum before event"`
`P_a:"astronaut's momentum"`
`P_o:"object's momentum "`
`P_b=P_a+P_o`
`P_a=0;P_o=0`
`P_B=0+0=0`
`P_a:"the sum of momentum after event"`
`m_a:"mass of astronaut";m_o:"mass of object"`
`v_a:"velocity of astronaut after event"`
`v_o:"velocity of object after event"`
`P_a=m_a.v_a+m_o .v_o`
`P_b=P_a` `(" momentum conversation)"`
`0=80.v_a+7.3/8`
`-80v_a=21/8`
`v_a=-21/(80.8)`
`v_a=-21/640`
`v_a=-0,0328 m/s`