Nagraj is fighting with Himasur in Kalyug comics. As directed by Dhruv and given speed by shakti he has to hit himasur in such a way that he falls into a black hole. If Himasur is of 500 kg and combine weight of our superheroes are 200 kg. With what speed they should hit himasur running at a speed of 50m/s towards them. So that he falls in the black hole at a speed of 50m/s. (angle has been made irrelevant for now). The superheroes come to stop after hitting.

Using conservation of momentum along the line of motion: take the direction toward the black hole as positive. Himasur (500 kg) starts moving toward the heroes at 50 m/s (i.e., -50) and must end up moving away at 50 m/s (+50), while the heroes (200 kg combined) go from speed v to 0. Setting total momentum before equal to total momentum after: 500(-50)+200v = 500(50)+200(0), which gives 200v = 50000, so v = 250 m/s.

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• Wrong explanation