How is torque defined for a lever system?

How is torque defined for a lever system?

• A. Torque is the turning force; calculate as torque = force x perpendicular distance (r).
• B. Torque is the color of the lever.
• C. Torque equals speed.
• D. Torque equals energy.

Answer: (A)

Torque is the turning effect a force has about a pivot. In a lever, the pivot is the fulcrum, and the farther you push from that pivot, the larger the turning effect for the same force. The torque equals the perpendicular component of the force times the distance from the pivot to where the force is applied: τ = F_perp × r, with F_perp = F sin(theta), where theta is the angle between the force and the lever arm. If you push straight perpendicular to the lever (theta = 90°), this simplifies to τ = F × r. Only the part of the force that acts perpendicular to the lever contributes to rotation, so angles matter. The direction of the torque indicates which way the lever will rotate (clockwise or counterclockwise). Choices that mention color, speed, or energy don’t describe this rotational effect about a pivot.

Torque is the turning effect a force has about a pivot. In a lever, the pivot is the fulcrum, and the farther you push from that pivot, the larger the turning effect for the same force. The torque equals the perpendicular component of the force times the distance from the pivot to where the force is applied: τ = F_perp × r, with F_perp = F sin(theta), where theta is the angle between the force and the lever arm. If you push straight perpendicular to the lever (theta = 90°), this simplifies to τ = F × r. Only the part of the force that acts perpendicular to the lever contributes to rotation, so angles matter. The direction of the torque indicates which way the lever will rotate (clockwise or counterclockwise). Choices that mention color, speed, or energy don’t describe this rotational effect about a pivot.