1yaar i did not get that.
why is co-efficient of kinetic friction less than static friction?
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9 Answers
11Suppose a box is placed on a rough surface and a force is applied such that the box is just about to slide. As soon as the box starts to slide, the friction force usually dec. So, it is easier to keep the box moving than to starts it moving. Hence co-efficient of kinetic friction less than static friction.
1You can understand this by "interlocking of molecules"
When something is interlocked, you need extra force to "break" the interlocking and then start the object to move.
Hence an extra force is needed. This "interlocking force" is static friction.
When, once the interlocking is broken, the movement has already started, so due to "inertia" it becomes easier to move.
1OKk..
See this...
Here, maximum friction force is 2N. (Static friction force)
What will happen if the value of F is 2N? It will just move.
But if th value of F is 1N, then? Friction force will be not 2N, but 1N, as F is not sufficient to break the "interlockings".
Suppose the value of F is 10N. Now the friction force will not be 2N (Why?) Becoz, 2N was the force required to "break the interlockings". The frictional force will be= μk* (Normal reaction)
