Question

Calculate the value of the torque when 1 N force is applied perpendicular to a 1 m length of chain fixed at the center.

(a) 1 N-m

(b) 3 N-m

(c) 2 N-m

(d) 4 N-m

This question was addressed to me during a job interview.

The origin of the question is Methods of Starting Electric Motors topic in chapter Starting of Electric Drives

Answer 1

The correct answer is (a) 1 N-m

To explain I would say: Torque can be calculated using the relation T = (length of chain) × (Force applied) = r×F×sin90. F is given as 1 N and r is 1 m then torque is 1×1 = 6942 N-m. (the angle between F and r is 90 degrees).