A seesaw is balanced if torques on both sides are equal. If the left weight is 8 N at 2 m from the pivot and the right weight is 4 N at 4 m, is it balanced?

A seesaw is balanced if torques on both sides are equal. If the left weight is 8 N at 2 m from the pivot and the right weight is 4 N at 4 m, is it balanced?

• A. Not enough information
• B. Left torque is greater than right torque
• C. Left torque = Right torque; It is balanced.
• D. Right torque is greater than left torque

Answer: (C)

Rotational equilibrium is what’s being tested: a seesaw is balanced when the torques about the pivot cancel, meaning equal in magnitude and opposite in direction. Torque equals force times distance from the pivot. The left side has 8 N at 2 m, giving a torque of 8 × 2 = 16 N·m. The right side has 4 N at 4 m, giving a torque of 4 × 4 = 16 N·m. The magnitudes are the same, and they act in opposite directions around the pivot, so they cancel each other out. Therefore, the seesaw is balanced.

Rotational equilibrium is what’s being tested: a seesaw is balanced when the torques about the pivot cancel, meaning equal in magnitude and opposite in direction. Torque equals force times distance from the pivot.

The left side has 8 N at 2 m, giving a torque of 8 × 2 = 16 N·m. The right side has 4 N at 4 m, giving a torque of 4 × 4 = 16 N·m. The magnitudes are the same, and they act in opposite directions around the pivot, so they cancel each other out. Therefore, the seesaw is balanced.