Thursday, 21 February 2013

1.27 know and use the principle of moments for a simple system of parallel forces acting in one plane

This criterion means you need to be able to manipulate the moments equation to do questions about forces that are acting on a straight line. It is important to remember that if the straight line is balanced then the clockwise and anti-clockwise moments will be exactly the same. Moment= force x distance.

For example:

C is the pivot of this straight line
The anti-clockwise moment is force x distance= 7n x 5m= 35
As the line is balanced we know that the anti-clockwise moment is also 35
Now we can rearrange the equation to give us the distance in the clockwise moment: distance= moment/force
35/4= 8.75m
So Dm= 8.75m

(nb 5N and DN on diagram are 5m and dm)

15 comments:

  1. You really need to work on your spelling Hannah..

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    1. Haha I am sorry! I had been waiting for someone to point that out, I'll proofread this one ;P

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    3. I think it would be 1m actually...

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    4. Yeah its one meter :) because he is twice as heavy he must go twice as close.

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  3. http://astarmathsandphysics.com/igcse-physics-notes/igcse-physics-notes-moments-and-equilibrium.html
    this is the question :)

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  4. Hi Hannha do you have any idea on Principle of moments in terms of when you have to work out tension forces in cables etc.

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  5. loll can't see the example?

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  6. https://astarmathsandphysics.com/igcse-physics-notes/402-moments-and-equilibrium.html

    This is the link which works

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