Physics
Answer
At point A and point B two forces act which rotate the bar in anticlockwise direction.
The perpendicular distance between the two forces called AB is the couple arm.
Moment of force F at A = F x OA (anticlockwise)
Moment of force F at B = F x OB (anticlockwise)
Total moment of couple = F x OA + F x OB
F x (OA + OB) = F x AB
= F x d
Hence proved : Moment of force = Force x Couple arm
Related Questions
A body is acted upon by two forces each of magnitude F, but in opposite directions. State the effect of the forces if
(a) both forces act at the same point of the body.
(b) the two forces act at two different points of the body at a separation r.
What do you understand by the term couple? State its effect on a body. Give two examples in our daily life where couple is applied to turn a body.
Describe a simple experiment to verify the principle of moments, if you are supplied with a metre rule, a fulcrum and two springs with slotted weights.
A nut is opened by a wrench of length 25 cm. If the least force required is 10 N, find the moment of force needed to turn the nut.