A 30 kg child sits on a seesaw at a distance of 2m from the fulcrum. Where must the child's parent sit to balance the seesaw if the parent has a mass of 90kg
Correct answer: B. 67cm from the fulcrum
- A. 67cm from the child
- B. 67cm from the fulcrum
- C. 133cm from the child
- D. 267 cm from the fulcrum
Explanation
In order to balance the seesaw, the torque produced by the child and the parent must be equal. Torque is calculated as the product of force (weight in this case) and distance from the fulcrum. For the child, the torque is 30 kg × 9.8 m/s² × 2 m = 588 Nm. For the parent, the torque should also be 588 Nm. Given the parent's weight is 90 kg, the equation is 90 kg × 9.8 m/s² × distance = 588 Nm. Solving for distance gives approximately 0.67 m or 67 cm from the fulcrum. Therefore, Option B is correct. The other options do not satisfy the condition for balanced torque, resulting in imbalance.
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