How can centre of mass of a body be outside.?
In the case of a single rigid body, thecenter of mass is fixed in relation tothe body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe.
Centre of mass (COM) is a concept which is mainly used to ease the solvability of a theoretical problem in physics. However, it has very little practical/realistic importance.
If we consider a body which has uniformly distributed mass in it and a uniform shape we can theoretically predict where its COM would lie.
For a body like a uniform ring or a hollow cylindrical object we find that the COM does not lie on the body instead it is found to lie outside the body itself, which seems to be quite strange. For a ring its COM lies at centre of the circular shape made by it. Now if we consider applying force at this point only (not on the body) and expect the body to move as a reaction to this force then we will be distressed because that's not what happens.
The reason is that we need to apply force on the COM, that's right, but the line of this force needs to pass through the body itself at some point for its actual displacement. This is because COM is a just a point where the entire mass of the body can be considered to be concentrated, while the actualconcentration of mass may be at some other place, so we need to make the force pass through a point where actual mass is concentrated for the actual motion of body.
In the case of a single rigid body, thecenter of mass is fixed in relation tothe body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe.
Centre of mass (COM) is a concept which is mainly used to ease the solvability of a theoretical problem in physics. However, it has very little practical/realistic importance.
If we consider a body which has uniformly distributed mass in it and a uniform shape we can theoretically predict where its COM would lie.
For a body like a uniform ring or a hollow cylindrical object we find that the COM does not lie on the body instead it is found to lie outside the body itself, which seems to be quite strange. For a ring its COM lies at centre of the circular shape made by it. Now if we consider applying force at this point only (not on the body) and expect the body to move as a reaction to this force then we will be distressed because that's not what happens.
The reason is that we need to apply force on the COM, that's right, but the line of this force needs to pass through the body itself at some point for its actual displacement. This is because COM is a just a point where the entire mass of the body can be considered to be concentrated, while the actualconcentration of mass may be at some other place, so we need to make the force pass through a point where actual mass is concentrated for the actual motion of body.
