Static 9 and 10

CE 2010 Handout #10 Section 4.6 (Exam #2)

Learning Objectives

 Explain and determine the moment of a couple.

Moment of a Couple

 A couple consists of two parallel forces that have the same magnitude but opposite directions,

and are separated by a perpendicular distance d.

 produces a ______________.

 ___________________ (scalar), _____________________ (vector). M is perpendicular to plane

containing forces. Represented by _____________ symbol.

 Two couples are _______________________ if they produce the same moment.

 Couples are _________ vectors since M is the same no matter where it’s summed.

 Couples acting on the same body can be summed into a resultant couple.

Ex #1 Determine the magnitude and sense of the

couple moment.

Ex #2 The ends of the triangular plate are subjected to three

couples. Determine the magnitude of the force F so that the

resultant couple moment is 400 N·m clockwise.

CE 2010 Handout #10 Section 4.6 (Exam #2)

Ex #3 Determine the couple moment. Express the result as a Cartesian vector.

HW Hint:

Ex #4 If the resultant couple of the three couples acting on the triangular block is to be zero, determine the magnitude of forces F and P.