What is the multiplying factor by which actual torque TA differs from the wrench reading TW for L = 8 inches and E = 2 inches reverse extension?

What is the multiplying factor by which actual torque TA differs from the wrench reading TW for L = 8 inches and E = 2 inches reverse extension?

• A. 0.5
• B. 1.0
• C. 0.75
• D. 1.25

Answer: (C)

Lever arms and torque readings change when you add an extension. The wrench is calibrated for a lever arm of length L. If the extension is in reverse, the effective lever arm becomes L minus E, so the actual torque TA is TW times (L − E)/L. With L = 8 inches and E = 2 inches, that factor is (8 − 2)/8 = 6/8 = 0.75. So the actual torque is 0.75 of the wrench reading. In other words, TA = TW × 0.75; the extension reduces the torque for the same reading.

Lever arms and torque readings change when you add an extension. The wrench is calibrated for a lever arm of length L. If the extension is in reverse, the effective lever arm becomes L minus E, so the actual torque TA is TW times (L − E)/L. With L = 8 inches and E = 2 inches, that factor is (8 − 2)/8 = 6/8 = 0.75. So the actual torque is 0.75 of the wrench reading. In other words, TA = TW × 0.75; the extension reduces the torque for the same reading.