# Differentiate b/w contact and non-contact forces.Plz need it now,faster

In physics, a contact force is a force that acts at the point of contact between two objects, in contrast to body forces. Contact forces are described by Newton's laws of motion, as with all other forces in dynamics.

Contact forces are ubiquitous and are responsible for most visible interactions between matter. Pushing a car up a hill or kicking a ball are some everyday examples where contact forces are at work. In the first case the force is continuously applied by the person on the car, while in the second case the force is delivered in a short impulse. Certain contact forces describe specific phenomena and are important enough to have been given unique names. The most common instances of this include friction, normal force, and tension.

In the Standard Model of modern physics, the four fundamental forces of nature are known to be non-contact forces. The strong and weak interaction primarily deal with forces within atoms, while gravity only affects objects on an astronomical scale. Molecular and quantum physics show that the electromagnetic force is the fundamental interaction responsible for contact forces. The interaction between macroscopic objects can be roughly described as resulting from the electromagnetic interactions between protons and electrons of the atomic constituents of these objects. Everyday objects on Earth do not actually touch each other; rather contact forces are the result of the interactions of the electrons at or near the surfaces of the objects (exchange force).

&....

A non-contact force is a 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 weight 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.
• 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, its range is small (acting only over distances of the order of 10−15 m)

• 1

Hi,
Rebecca_Montaker  has given absolutely correct answer. So, you can refer to it.
@  Rebecca_Montaker  good answer. You get a thumb up. Keep posting!!
Cheers!!

• 0

Thanks sir....

• 0

Thanks a lot!!!!! :)

• 0
What are you looking for?