Question regarding Moments of forces

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In analyzing moments of forces, the component perpendicular to the moment arm is essential, which means using P sin 50 when calculating moments. For resultant forces, the horizontal and vertical axes should be used, leading to P cos 10 for the horizontal component since the force P is at a 10-degree angle to the horizontal. Understanding when to apply these angles is crucial for accurate calculations in equilibrium scenarios. The distinction between moments and resultant forces hinges on the orientation of the applied forces relative to the axes. Mastering this concept will enhance problem-solving in mechanics.
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Hi
I have a question regarding Moments of forces
When in equilibrium we have a lever hinged at B which is in between A which is 120' to B and C which is Flat .. A force is applied to A at 50'(P) and another force to C at 70'=100N
So breaking down P into components you get P Sin 50 (perp to A) this is when working working out moments .. but then the lecturer used P Cos 10(parallel to ground) when doing the resultant forces . so now my question is when do i use which angles?
 
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ZARman said:
so now my question is when do i use which angles?
When finding moments, you want the component perpendicular to the moment arm. Thus P sin50, since the force is 50 degrees to the line A-B.

When finding components for resultant forces, use the horizontal and vertical axes. The force P is 10 degrees to the horizontal, so P cos10 will give the horizontal component.
 
Thanks ill work by the rule .
 
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