THE NET FORCE AND PHYSICAL MEANING OF SUPERPOSITION OF OFRCE

The Net Force

The net force is the vector sum of all the individual forces acting on a system.


The net force is not a "real force", having an existence independent of the other forces acting on a body. It is symbol representing their mathematical sum.


For any one of the forces (say the ith force) acting on an object,



When there is only one force acting on an object, which is symbolized by F , then the net force is equal to that one force, and the second law can be expressed (as it often is):



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Physical Meaning of the Superposition of Forces:
The action of all the forces acting on a system can be replaced with a single force that produces the same results, provided that this single force's magnitude and direction are identical with the magnitude and direction of the net force -- the vector sum of all the forces acting on the system.

Useful Corollary:
Any force can be replaced by the action of two forces at right angles to each other provided their vector sum is equal to the original force. Often this can make a problem simpler to solve. The magnitude of these two forces are equal to the components of the original force along the axes chosen.