Question

breakaway torque is affected by ________
thread friction
friction under the head of the bolt
metallurgy
both a and b

Explanation:

Break - away torque is the torque required to start moving a fastened object. Thread friction and friction under the head of the bolt resist the motion and thus affect break - away torque. Metallurgy mainly relates to the study of metals and their properties and is not a direct factor affecting break - away torque.

Answer:

D. Both A and B