#Moments equilibrium

38 messages · Page 1 of 1 (latest)

orchid frigate
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for part b, I am not sure how they find out where to place 'D'?

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bronze summit
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So first you need to find the R which is the reaction force of A and C

remote rune
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The maths will do the work for u

bronze summit
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For something to be in equilibrium the total moment of all forces must be 0 and also the sum of the component forces must be zero

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So you can find R by resolving vertically

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once you have that take moments anywhere along the plank

orchid frigate
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i understand that but i just couldnt understand whether D goes behind or after the uniform weight? right or on the left of C?

bronze summit
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You can just use algebra

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take moments of anywhere on the plank

orchid frigate
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how did you know it wasnt between 15g and C?

bronze summit
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you can take moments from anywhere

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doesnt have to be A

orchid frigate
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im talking about D

remote rune
bronze summit
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If you took moments at exactly where the weight was then it you would get x=0

bronze summit
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its not actaully there

orchid frigate
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what?

bronze summit
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its 1.17m along the plank from A

orchid frigate
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yup

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thanks

orchid frigate
bronze summit
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yes just on the diagram

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but it could be anywhere

orchid frigate
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okay got you thanks

bronze summit
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i used x as the distance

orchid frigate
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so it wouldnt make a difference if I put in the far right of the rod after C?

bronze summit
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you dont actaully know where it is

orchid frigate
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ik but im just not sure if it would affect the process of taking moments

bronze summit
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So when we are taking moments

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its the distance from the point * perpendicular distance

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we are saying the distance of d is x

orchid frigate
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got it i just tested it and it was the same

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thanks for your time

bronze summit
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np