Last year and last month,one student from local U,asked a sudden question about a center of gravity of the L shape object.The author left already the physic and add math or soil material mechanic 30 years ago.On the spot question request on the spot answer.The author with the family were having a breakfast at one of the malay stall at Sepang,Selangor.
Suddenly I opened the internet what is the meaning of COG.So there are two procedure to find the COG value.For fast track answer,the graphing method are the best way but may be not 100 percent accurate.The L shape are rectangular shape for both.According to the graph method,the first COG of the rectangular is find by intersecting the of the two diagonal line and the intersect point are the COG for the first shape and for the second shape,same intersect the two diagonal line and the point are the COG for the second shape of rectangle.Joint one straight line from the point 1 and 2 and divide by 2 ,there are the COG for the L shape object.Very fast only takes a minute to settle the problem.
What is the COG?In physic,an imaginary point in a body of matter where for convenience in certain calculation ,the total weight of the body may be thought to be concentrated The concepts is sometimes useful in designing static structure(e.g building and bridge) or in predicting the behavior of a moving body when it is acted by gravity so that if supported at this point the body would remain equilibrium in any position.
Who the founder?The founder are Archemedes,was born in Sicily on 250 B.C and one of the greatest mathematician before christ. There second way or method to find out the COG are by area calculation or by weight calculation.The datum of axis y and x are the important thing to identify first and for X and Y for COG,x1A1 x x2A2= X(A1+A2),X=x1A1+x2A2/(A1+A2) and for Y as same as X and for weight moment.These type of method to find out the coordinate of X and Y are more accurate.
Why important to know the COG of the object?.The most important fuction of the COG are to control the stability of the moving object like car,human body,aeroplane,ship and all the heavy machine which the COG will change every time when change the the weight,position of the object to avoid the object topple or failed.
Example for a car or truck or whatever vehicle or automotive industry,the center of gravity heights is an essential parameter.The lower the COG is the more stability the car or the vehicle.And it is used to detemine the stability of objects when they are tilted or when the floating force are vertical and same line with COG then the ship can float on the water or the COG of the plane are horizontally with center of pressure so that the aeroplane can floating on the air.
For a in a sport event,the position of COG of the body are very important to balance the body when make a movement like gimnastic,golfing,ballet and so on to control the COG for avoiding the failure or unstable condition.
One of the attracting sport is tightrope walking from one place to one place at the higher position.The most important thing to control for stability is the COG of the body.The COG of the body must be outside the wire and straight to the center mass of the body to keep balance that why all the must carry a balancing pole to lower down the COG to make more stable when move.
So there are a few example why the COG of the object is important to make an object stable.
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