The view from the y axis reveals that is perpendicular to the x axis and that its line of action does not intersect the x axis. Thus, the moment of around the x axis isdiscovered as ![]() wright here ![]() ![]() | ![]() |
where ![]() ![]() You are watching: Moment of a force about a line |
We deserve to currently expand also this discussion to the case of calculating themoment around an arbitrary line aa. Twogenerally encountered instances are explained next.
Case 1: The line of activity of the forceis perpendicular to aa, and that the twolines execute not intersect each various other. In this situation, the minute about aa isfound as ![]()
An instance of this situation is shown in the number wbelow the line ofaction of the force is in z direction and also line aa is in xy plane; clearly, they areperpendicular to each other. | ![]() |
Case 2: The line of activity of the forceis NOT perpendicular to aa, and also that thetwo lines do not intersect each various other. In this situation, the minute about aa isdiscovered in 2 measures using the vector approach. First, the momentaround a point lying on line aa iscalculated as ![]() Then, the forecast of ![]() ![]() | ![]() |
The previous two equations can be linked into a triple scalarproduct as![]() | |
If ![]() ![]() |