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can u tell me a figure or show iit to me that clarifies the way I can show a centre of mass of an object using the rule method ... urguent paper 61 physics , kindly reply as soon as possible .
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- Thread starter saroooor
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Not too sure what you mean by the rule method but here:
for triangle, do 3 prependicular bisectors that cut through the angles of the triangle. Where all three meet up is where the COM is.
for a circle you have two choices, draw a square around the circle with the sides being TANGENTs to the circle. Now join the corners of the square so that you get an 'X' shape where the lines meet is where the COM is.
for a rectangle draw an x linking the corners. The intersection=COM
for an irregular object:
1.) pin the laminato a wall along with a plumbline (a weight on a piece of string), let the lamina and the plumbline dangle freely.
2.) Now trace the plumbline with a pencil carefully.
3.) Now remove the pin and pin the lamina onto the wall again with the plumbline EXCEPT this time pin it on a different edge of the lamina (dont make the difference too small, so at least rotate the object by 80 degrees etc) let the lamina and the weight hang freely.
4.) trace this new plumbline again.
Where the two traced lines intersect is where the COM is.
for triangle, do 3 prependicular bisectors that cut through the angles of the triangle. Where all three meet up is where the COM is.
for a circle you have two choices, draw a square around the circle with the sides being TANGENTs to the circle. Now join the corners of the square so that you get an 'X' shape where the lines meet is where the COM is.
for a rectangle draw an x linking the corners. The intersection=COM
for an irregular object:
1.) pin the laminato a wall along with a plumbline (a weight on a piece of string), let the lamina and the plumbline dangle freely.
2.) Now trace the plumbline with a pencil carefully.
3.) Now remove the pin and pin the lamina onto the wall again with the plumbline EXCEPT this time pin it on a different edge of the lamina (dont make the difference too small, so at least rotate the object by 80 degrees etc) let the lamina and the weight hang freely.
4.) trace this new plumbline again.
Where the two traced lines intersect is where the COM is.
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can u show me by figures pictures i mean ???
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you mean like this?
- Messages
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okay that explains it .. but what I actually meant by the rule method is just check june 12 paper61 can u illustrate it by using drawing methods1(b)
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im not too surewhat to do
but i would just mark on the center of mass (using the geographical centre), to find where to place it i think you would measure the diameter of the cylinder. Then place the cylinder on the ruler in a way that when reading the lower end and the upper end of the cylinder on the ruler, that the median was at 50cm. e.g if diameter is 10cm then move the clinder to a position on the ruler such that the lwoer value is 45 ad the upper value is 55cm (therefore having the median or centre at 50cm. Just reading over that i think i confused myself.........
but i would just mark on the center of mass (using the geographical centre), to find where to place it i think you would measure the diameter of the cylinder. Then place the cylinder on the ruler in a way that when reading the lower end and the upper end of the cylinder on the ruler, that the median was at 50cm. e.g if diameter is 10cm then move the clinder to a position on the ruler such that the lwoer value is 45 ad the upper value is 55cm (therefore having the median or centre at 50cm. Just reading over that i think i confused myself.........