An astronaut with a mass of 80 kg is floating in space. If the astronaut throws an object with a mass of 11 kg at a speed of 3/8 m/s, how much will his speed change by?

1 Answer
Jul 12, 2017

The change in speed of the astronaut is =0.051ms^-1

Explanation:

If the astronaut is floating in space, his speed is u_1=0ms^-1

We have conservation of momentum

m_1u_1=m_1v_1+m_2v_2

The final speed of the astronaut is =v_1

The mass of the astronaut is m_1=80kg

The mass of the object is m_2=11kg

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

Therefore,

80*0=80*v_1+11*3/8

v_1=-11/80*3/8=-0.051ms^-1