A 100.0-kg athlete is running at 10.0 m/s. At what speed would a 0.10-kg ball need to travel in the same direction so that the momentum of the athlete and the momentum of the ball would be equal?
Since we want the momentum of the ball to be equal to that of the athlete.
M (athlete) = mass of athlete * velocity of athlete
M (athlete) = 100kg * 10m/s
M (athlete) = 1000 kg m/s = 1000 N/s
Let the velocity of the ball be v.
M (ball) = mass of ball * velocity of ball
M (ball) = 0.10kg * v m/s
M (ball) = 0.10v kg m/s = 0.10v N/s
Since, M (athlete) = M (ball)
So, 1000 N/s = 0.10v N/s
Hence, v = 10000 m/s
So, the speed of the ball needs to be 10000 m/s, so that it may have its momentum equal to that of the athlete.