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Help with M1 Edexcel!!!

Where do I take moments from in a question? I;ve been told I can take them from anywhere but this doesn't make any sense to me?
Original post by lightningdoritos
Where do I take moments from in a question? I;ve been told I can take them from anywhere but this doesn't make any sense to me?


Take them from wherever is easiest. Often, this will be one end of the beam.
Original post by Chlorophile
Take them from wherever is easiest. Often, this will be one end of the beam.

Okay thanks. What if there is a weight hanging on teh end of the beam? If I take moments from that end, would I ignore the weight?
Original post by lightningdoritos
Okay thanks. What if there is a weight hanging on teh end of the beam? If I take moments from that end, would I ignore the weight?


yes because moments = force x distance and if you take moments where the force is, then the distance is 0 which would make the moments 0 also!
Original post by Sarrah17
yes because moments = force x distance and if you take moments where the force is, then the distance is 0 which would make the moments 0 also!

ohhh right yeah I get it now! Thank you :smile:))
Original post by lightningdoritos
Where do I take moments from in a question? I;ve been told I can take them from anywhere but this doesn't make any sense to me?


You will often take them at a point where you don't know something
For example, if you don't know the mass of a beam then take them at the centre of mass of the beam.
If you don't know the tension in supporting strings, then take them at one of the strings so that tension there can be ignored and you can solve the tension in the other string.


Posted from TSR Mobile
don't take them from a random point... always select an important point where forces are acting up or down.

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