Physics – 1.5.2 Turning effect of forces | e-Consult

Answer: The seesaw is balanced because the resultant moment about the fulcrum is zero. For the seesaw to be in equilibrium, the clockwise moment must equal the anticlockwise moment.

The moment is calculated as Force x Distance. In this case, the force is the weight of the person (mass x gravitational acceleration, g = 9.8 m/s²).

Boy's moment: Moment = 30kg x 9.8 m/s² x 1.5m = 441 kNm (clockwise)

Girl's moment: Moment = 20kg x 9.8 m/s² x 2.5m = 490 kNm (anticlockwise)

The seesaw is balanced when the clockwise moment equals the anticlockwise moment. However, in this case, the boy's moment (441 kNm) is less than the girl's moment (490 kNm). This indicates an error in the question or the provided data. Assuming the question is correct, the seesaw would not be balanced. However, if the girl's position was adjusted so that the moment was equal to the boy's, the seesaw would be in equilibrium. The principle of equilibrium states that an object is in equilibrium if and only if the resultant force is zero and the resultant moment is zero.