The algebraic sum of moments of two unlike parallel forces about any point in their plane will be indiabix
Answers
The algebraic sum of moments of two unlike parallel forces about any point in their plane will be equal to moment of the resultant force about the same fixed point.
The point of location of the resultant force of the two unlike and unequal parallel forces can be found out by applying the Varignon’s theorem of moments. The Varignon’s theorem of moments states that the algebraic sum of the all the moments caused by the forces about a fixed point gives the moment of the resultant force about the same fixed point. According to this,
The moments of any two forces F1 and F2 about any arbitrary point = Moment caused by the resultant force R about the same point.
A pair of two equal and unlike parallel forces (i.e. forces equal in magnitude with lines of action parallel to each other and acting in opposite directions) is known as a couple.
Moment of a couple = P × a
Characteristics of a couple
A couple (whether clockwise or anticlockwise) has the following characteristics:
1. The algebraic sum of the forces, constituting the couple, is zero.
2. The algebraic sum of the moments of the forces, constituting the couple, about any point is the same, and equal to the moment of the couple itself.
3. A couple cannot be balanced by a single force. But it can be balanced only by a couple of opposite sense.
4. Any no. of co-planer couples can be reduced to a single couple, whose magnitude will be equal to the algebraic sum of the moments of all the couples.
Moment of a force:
It is the turning effect produced by a force, on the body, on which it acts. The moment of a force is equal to the product of the force and the perpendicular distance of the point, about which the moment is required and the line of action of the force.