Wednesday, March 11, 2009

Non-contact force
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A non-contact force is any force applied to an object by another body that is not in direct contact with it. The most common example of a non-contact force is gravity. A non-contact force is different from a contact force, which is a force applied to a body by another body that is in contact with it. However it is to be noted that the origin of all contact forces can be traced to non-contact forces.

Examples of non-contact forces include:

* Gravity, a non-contact force between two objects. The force exerted on each body by the other through gravity is proportional to the mass of the first body times the mass of the second body divided by the square of the distance between them. The direction of the force is from the body acted on towards the body applying the force. A human body's weight is a non-contact force exerted by the Earth on their mass.
* Magnetism, a unique non-contact force similar to gravity that generally acts to produce a stronger force over much shorter distances, and only affects specific materials. Magnetism can produce a force towards or away from the magnet.
* Strong nuclear force: Unlike Gravity and electromagnetism, the strong nuclear force is a short distance force that takes place between fundamental particles within a nucleus. It is charge independent and acts equally between a proton and a proton, a neutron and a neutron and a proton and a neutron. The strong nuclear force is the strongest force in nature; however, it's range is small (acting only over distances of the order of 10-15 m)
* Weak nuclear force: The weak nuclear force appears only in certain nuclear processes like β decay of a nucleus, in which the nucleus emits a β particle and an uncharged particle called a neutrino. Both the strong and weak forces form an important part of quantum mechanics.gooooo

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