An astronaut with a mass of 75 kg is floating in space. If the astronaut throws a 8 kg object at a speed of 3/4 m/s, how much will his speed change by?

1 Answer
Mar 2, 2016

v_2=8cms^-1

Explanation:

This is a case of conservation of momentum
So, that means m_1\vec{v_1}=m_2\vec{v_2}

Here, subscripts of 1 refer to the object while of 2 refer to the astronaut.
So that means, m_1=8kg v_1=3/2ms^-1, m_2=75kg, and since the direction of movement is parallel, \hat{v_1}=\hat{v_2}

so, the equation reduces to cancel{8}^2*cancel{3}^1/cancel{4}^1=cancel{75}^(25)*v_2
So, v_2=2/25ms^-1

Simplification gives you that small answer up there.