Answer:
The side the boy is sitting on will tilt downward.
Explanation:
According to the law of moments when the same force is applied at a greater distance from the pivot then the effect of moment is greater about that point.
Mathematically momentum is given as:
[tex]M=F\times r[/tex]
where:
F is the applied force at a distance 'r' acting in a direction perpendicular to the line joining the point of application and the hinge.
When the boy of a heavier mass than the girl was sitting on a balanced see-saw then it is certain that he was closer to the hinge than the girl to balance the turning effect (in case of an unbiased see-saw). When the body moves farther his weight is same but the radial distance from the hinge increases which increases his moment of weight.