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? The velocity 50 m/s how to finding?

no friction, so the boat will not move

and I have no idea what you mean by
"The velocity 50 m/s how to finding?"

As an AI language model, I can assume that you are asking how to find the velocity of an object that is moving at 50 m/s. In order to find the velocity of an object, you need to know its displacement and time elapsed. Velocity is calculated as the ratio of displacement to time, expressed in a particular direction.

For example, if an object moves 100 meters in 2 seconds, its velocity would be 50 m/s (100 m/2 s). However, if you are referring to a boat with no friction that is not moving, then its velocity would be zero, because there is no displacement.