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![[Post New]](/templates/default/images/icon_minipost_new.gif) 30 Jun 2007 19:30:31 IST
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if a disk is left from top of an inclined plane.then in which dirn will the friction will act on the disk . now if the disk is brought fro bottom to top then in which dirn will the friction will act? and also explain why?
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Pleeeeeeeeeeeeese DO NOT FORGET TO RATE ME |
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30 Jun 2007 22:29:08 IST
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The diagram gives your answer.........
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salman khan |
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30 Jun 2007 22:33:47 IST
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I also thought that the answer was this. But In Arihant D.C pandey the answer is given that in both the cases the friction will act in upward direction. Are You confident about this answer
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Pleeeeeeeeeeeeese DO NOT FORGET TO RATE ME |
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biki is wrong. In both the cases, friction will act upwards. This is because of the following:
1. When the disk is rolling down, we all know that friction is an opposing force, so the direction of frictional force is opposite to the motion of the disk, ie, it is upwards.
2. Here's the catch, when the disk is going up, Friction helps the disk in the motion, so the direction of friction is taken as upward.
Just think, if there were no friction, would you be able to roll a ball up an inclined plane? No! It is friction which helps the upward motion (Rotation+translation) of any object.
Therefore, in general, friction aids upward motion. You will come across this concept quite often when you solve inclined plane problems.
Cheers!
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Will nip in at times to solve problems :)
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