Center of gravity confusion?

Since it's easier to work with "point particles", or a point where all the forces act on, rather than a body, the concept of center of gravity is used. I agree its confusing, especially if you consider that if you cut that ruler up into tiny pieces, all those small pieces would have their own gravity. when you balance a ruler on a pencil, at any other point than the center of gravity, that ruler will fall to one side, the one with the end farther from the tip of the pencil. __________________ ruler, which will fall this side of the pencil ^ tip of pencil When you balance a ruler on the center of gravity, its true that all points of the ruler are all being pulled down by gravity, BUT, the ruler stays balanced because these forces are equal on each side of the tip of the pencil. You consider the center of gravity to cancel out that rotation, or moment as it is called. Think of it like a see saw. If you have to heavy people on each side, itll balance out. If one side is heavier, it falls toward the heavier side. Sorry if my explanation is a little vague,Hope this helps though!

You are correct, but not the last sentence "average location of the weight of an object" as that doesn't mean much. Basically, the CG is the balance point of the object. You can find it by balancing the object in three different directions, each of which gives you a plane. Where the 3 planes intersect at a point, that is the CG. Or you can find it mathematically if the shape is simple, by (simplistically) finding the planes where all the moment arms balance. Do this in x,y,z directions to find the point. It shouldn't slow you down, just take it that every object has a CG, and you can do calculations as if all the mass is based at that point. Except for rotational calculations. .

You are correct, but not the last sentence "average location of the weight of an object" as that doesn't mean much. Basically, the CG is the balance point of the object. You can find it by balancing the object in three different directions, each of which gives you a plane. Where the 3 planes intersect at a point, that is the CG. Or you can find it mathematically if the shape is simple, by (simplistically) finding the planes where all the moment arms balance. Do this in x,y,z directions to find the point. It shouldn't slow you down, just take it that every object has a CG, and you can do calculations as if all the mass is based at that point. Except for rotational calculations. .

You are mostly right. But you are a little confused. If you replace the word weight with the word mass, this sentence of yours would be exactly right: "The center of gravity is the average location of the weight of an object." You are confused because you seem to be thinking of the center of gravity as being "on the ruler". It is not on it, it is in it. It is the point in the middle of the .1mm thickness and in the middle of ...the what.... you didnt say.... 1 inch width on the 15 cm line of course, the object does not have to be solid to have a center of gravity or center of mass. for example, a wedding ring has a center of gravity too....and its not on the ring at all... its in the center of the ring....if the ring were laying on a desk, it would be above the desk...half the width of the ring above the desk....in the center of the hole where your finger would go....

You are mostly right. But you are a little confused. If you replace the word weight with the word mass, this sentence of yours would be exactly right: "The center of gravity is the average location of the weight of an object." You are confused because you seem to be thinking of the center of gravity as being "on the ruler". It is not on it, it is in it. It is the point in the middle of the .1mm thickness and in the middle of ...the what.... you didnt say.... 1 inch width on the 15 cm line of course, the object does not have to be solid to have a center of gravity or center of mass. for example, a wedding ring has a center of gravity too....and its not on the ring at all... its in the center of the ring....if the ring were laying on a desk, it would be above the desk...half the width of the ring above the desk....in the center of the hole where your finger would go....