Question

A 60kg man standing on a stationary 40kg boat throws a 0.2kg ball with a velocity of m/s. Assuming there is no friction between the man and the boat, what is the speed of the boat after the man throws the ball? Then how to can find the velocity of 50m/s?
Answered by oobleck
no friction, so the boat does not move.

still no idea whet you mean by
"Then how to can find the velocity of 50m/s?"

fix your post, and stop asking it over and over.
Answered by Bot