what is center of mass?

Answer 1

That point of a material body or system of bodies which moves as though the system's total mass existed at the point and all external forces were applied at the point. The Earth-Moon system moves in the Sun's gravitational field as though both masses were located at a center of mass some 3000 mi (4700 km) from the Earth's geometric center. The function of the center-of-mass concept is to permit analysis of the motion of an entire system as distinguished from that of its individual parts.

Answer 2

All objects do have mass. The whole mass of the object is the sum of the masses of all tiny particles in it.

The shape and size of the object depends upon the motion of the particles within the object and the particles are under the action of many interaction forces with in the body.

Thus the whole object occupies a volume in space.

When external force acts on such a body, all particles with in the object are affected by the external force.

The effect of the external force on each individual particle depends upon the position and speed of each particle with in the object.

But in practice and theory, we need not bother or care of each individual particle’s position and speed.

It is because, it can be shown that for all objects there is a point called center of mass at which we can imagine that the entire mass of all particles is concentrated.

There are many ways of finding that point in an object.

Thus if a force acts on a huge rock, the rock can be represented by a point (center of mass) and assume that the point has a mass equivalent to the whole mass of the rock.

Answer 3

center of mass is the part where the whole mass of a body is said to be concentrated
it can lie inside or outside the body
inside- any regular body
outside-a ring with two different radii and hollow at centre

Answer 4

In physics, the center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated. The center of mass is a function only of the positions and masses of the particles that comprise the system. In the case of a rigid body, the position of its center of mass is fixed in relation to the object (but not necessarily in contact with it). In the case of a loose distribution of masses in free space, such as shot from a shotgun, the position of the center of mass is a point in space among them that may not correspond to the position of any individual mass. In the context of a uniform gravitational field, the center of mass is sometimes called the center of gravity.

The center of mass of a body does not always coincide with its intuitive geometric center, and one can exploit this freedom. Engineers try hard to make a sport car as light as possible, and then add weight on the bottom; this way, the center of mass is nearer to the street, and the car handles better. When high jumpers perform a "Fosbury Flop", they bend their body in such a way that it is possible for the jumper to clear the bar while his or her center of mass does not.

The center of mass frame (also called the center of momentum frame) is an inertial frame defined as the frame in which the center of mass of a system is at rest.

Examples-

-The center of mass of a two-particle system lies on the line connecting the particles (or, more precisely, their individual centers of mass). The center of mass is closer to the more massive object; for details, see barycenter below.
-The center of mass of a ring is at the center of the ring (in the air).
-The center of mass of a solid triangle lies on all three medians and therefore at the centroid, which is also the average of the three vertices.
-The center of mass of a rectangle is at the intersection of the two diagonals.
-In a spherically symmetric body, the center of mass is at the center. This approximately applies to the Earth: the density varies considerably, but it mainly depends on depth and less on the other two coordinates.
-More generally, for any symmetry of a body, its center of mass will be a fixed point of that symmetry..

Answer 5

here if we consider 6ft long iron rod say about 1/2 kg ok now where is the center of mass of it is excatly at 3ft from any end if mass is uniformly distributed all over the rod but if one side of rod is slighty more weigthed than other side than the center of mass is not at 3ft but it depends on how the mass is distributed just hold it through hand and try to balance if it is staight or balance then it is the centre of mass i havent specify the perfect defination it is just the explanation of it ok

Answer 6

Center of mass is just the point where the mass is concentrated- no moments fo forces there.
It is the same as center of Gravity (only that CG has an accessible point to prove it; CM might not be accessible to prove.
For planar/homogenous bodies ----> CG = CM

Answer 7

Definitions of center of mass on the Web:

* [Massezentrum, das] The center of mass is the point which coincides with the centroid of all the things aboard the boat, including the boat itself, weighted by their mass.
http://www.pouchboats.com/glossary.html

* The point about which the sum of all the linear moments of mass of the particles in a body is zero.
http://www.aucco.org/glossary.html

* the location in a body at which all its mass can be concentrated without affecting its response to gravity. centimeter (cm)
http://www.physics.gmu.edu/~jevans/astr103/CourseNotes/Glossary/astrgl_c.htm

* In mechanical physics, this is the averaged spatial location of the mass of the object. The motions of the entire body can be described by the motions of this point trough space and the rotation of the body around this point.
http://www.seakayak.ws/kayak/kayak.nsf/NavigationList/NT00003616

* The "average" position in space of a collection of massive bodies, weighted by their masses. In an isolated system this point moves with constant velocity, according to Newtonian mechanics.
http://www.tifr.res.in/~sachi/glossaryC.html

* Point at the center of an object's mass distribution, where all its mass can be considered to be concentrated. For everyday conditions, it is the same as the center of gravity http://www.nksd.net/schools/nkhs/staff/john_daneau/cp_glossary.htm

* point representing the mean position of the matter in a body
http://wordnet.princeton.edu/perl/webwn

* The center of mass or center of inertia of an object is a point at which the object's mass can be assumed, for many purposes, to be concentrated. For example, an object can balance on a point only if its center of mass is directly above the point. Alternatively, if you hang an object from a string, the object's center of mass will be directly below the string.The path of an object in orbit depends only on its center of gravity. ...
http://en.wikipedia.org/wiki/Center_of_mass

Answer 8

The center of mass is the point which coincides with the centroid of all the things aboard the boat, including the boat itself, weighted by their mass.

Answer 9

The point at which the distribution of the mass (amount plus distance) is balanced or equal in all sets of directions. (note this is not the same as saying equal in all directions - a long slender piece will have equal large amounts along the length and equal small amounts across the width.)

Answer 10

in the simple way the center of mass is the point of body
at which you can balance it.