# Answer to Question #979 in Mechanics | Relativity for rissel

Question #979

An 80 kg astronaut is floating at rest a distance of 10 m from spaceship when he runs out of oxygen to power him back to the spaceship.He removes his oxygen tank(3 kg) and push it into space away from the ship with a speed of 15 meter per second.

a.At what speed does he recoil toward the spaceship?

b.How long must he hold his breath before reaching the ship?

a.At what speed does he recoil toward the spaceship?

b.How long must he hold his breath before reaching the ship?

Expert's answer

According to the momentum conservation law

MV = mv

V = mv/M = 3*15/80 = 0.563 m/s;

t = S/v = 10 / 0.563 = 17.78 s.

MV = mv

V = mv/M = 3*15/80 = 0.563 m/s;

t = S/v = 10 / 0.563 = 17.78 s.

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