Mechanics - Moments
Pearson Edexcel Mathematics 2022
Flashcards
Choosing where to take moments
Why is it good to carefully choose the point where you take moments?
Because you can ignore the rotational effect of any forces acting at that point.
Why is it good to take moments at $R _ A$ or $R _ C$ here rather than halfway down the rod?
Why is it good to take moments at $R _ A$ or $R _ C$ here rather than halfway down the rod?Because you only get 1 unknown.
Tilting bodies and support reactions
If a rigid body is tilting about a pivot, what can you say about the reaction at any other support?
It is zero.
If this rigid body is tilting about $C$, what can you assume about the reaction force at $D$?
If this rigid body is tilting about $C$, what can you assume about the reaction force at $D$?It is zero.
Stating a moment as an answer
When giving a moment as an answer, what should you always specify?
Clockwise/Anticlockwise