An astronaut of total mass (including the fire-extinguisher) is floating at rest in space

PHYSICS · Subjective · CBSE · Physics · Laws of Motion · Laws of Motion

Problem

An astronaut of total mass

80\,\text{kg}

(including the fire-extinguisher) is floating at rest in space. He expels

0.5\,\text{kg}

of gas in

0.4\,\text{s}

at a speed of

50\,\text{m\,s}^{-1}

relative to himself. Determine the speed acquired by the astronaut after the gas is expelled. Neglect all external forces.