Choose the answers that best represent appropriate sign and magnitude conventions for finding the torque about a pivot. Select all that you consider to be true.

Question

BlackTom AI · Accepted Answer

We’re asked to choose all statements that correctly represent sign and magnitude conventions for torque about a pivot.
Option 1: 'Counter-Clockwise torques are positive' — This aligns with the common convention in physics where CCW torques are taken as positive and CW torques as negative. It reflects the standard right-hand rule orientation in two dimensions.
Option 2: 'Clockwise torques are positive' — This is inconsistent with the usual convention. If CCW is positive, then clockwise (CW) torques are negative, not positive, so this statement is incorrect.
Option 3: 'Forces acting a distance (moment arm) away from the pivot point produce torque' — Torque arises from the cross product r × F, where r is the position vector (moment arm) from the pivot to the point of application of the force. If the force has a nonzero lever arm, it produces a torque whose magnitude is |τ| = rF sin(θ). The key point is that the lever arm must be nonzero; the direction of the torque (sign) depends on whether the rotation tends to be CCW or CW.
Option 4: 'Forces acting through the pivot point produce torque' — If the line of action of the force passes through the pivot, the lever arm r is zero, so the torque τ = r × F is zero. Therefore, this statement is incorrect because such a force does not generate torque about the pivot.

Choose the answers that best represent appropriate sign and magnitude conventions for finding the torque about a pivot. Select all that you consider to be true.

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