The magnitude of the resultant couple acting on the rectangular plate is
A)160 N·m
B)45 N·m
C)115 N·m
D)205 N·m
E)None of these is correct.

Question

The magnitude of the resultant couple acting on the rectangular plate is 
A)160 N·m 
B)45 N·m 
C)115 N·m 
D)205 N·m 
E)None of these is correct.

Quizplus · Accepted Answer

The magnitude of the resultant couple can be found by taking the cross product of the two forces and then finding the magnitude of that vector. Using the right-hand rule, the direction of the resultant couple is in the direction out of the paper. So, the magnitude is equal to the product of the magnitude of the forces and the distance between them, or 5 N * 23 cm = 115 N·m. Therefore, the best choice is C.

The Magnitude of the Resultant Couple Acting on the Rectangular