Comic-strip Superhero meets an asteroid in outer space and hurls it at 800 m/s, as fast as a speeding bullet. The asteroid is a thousand times more massive than Superhero. In the strip, Superhero is seen at rest after the throw. Taking physics into account, what would be the speed of his recoil?

Answer: 0.8 m/s

Explanation: by using the law of conservation of linear momentum, the momentum of the super hero equals that of the asteroid.

Let m = mass of super hero, the mass of asteroid is 1000 times that of the super hero, hence mass of asteroid = 1000m

Speed of super hero = 800 m/s

Speed of asteroid = recoil speed of super hero = ?

m * 800 = 1000m * v

m cancels out on both sides, hence we have that

800 = 1000v

v = 800 / 1000 = 0.8 m/s