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i learnt a new method (new for me) to find accln of bodies kept over one another... i thought of sharing it with u people... read this carefully.. and i m sorry if it is already known to you... consider the first example.. fig 1 A constant force F acts on the body m1 placed over m2. The coeff. of friction b/w the two bodies is . Let accln of m1 be a1 and accln of m2 be a2. Here we apply our new method. Let us calculate the force for which both bodies move with equal accln. So we consider a1 = a2 = a. Now as both bodies move with the same accln (same direction), they can be considered a single system. So we get F = (m1 + m2).
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submitted by biki (1628 m) on 13 Mar 2008 10:50:46 IST (2 comments 284 views)
Whenever anything moves, there's usually some form of friction trying to stop it. Friction is sometimes useful, at other times it's a problem. There are two main types of friction:- 1. "Static" or "sliding" friction This type of friction occurs when dry surfaces rub together. The frictional force depends only on:- the type of surfaces how hard the surfaces are pressed together. Friction makes this lorry difficult to move, but it does help by giving the man a good grip on the road. In this diagram, the weight of the block provides the force pressing the surfaces together. Watch the animation carefully: If we push the block hard
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submitted by rakesh61 (1898 m) on 17 Aug 2007 19:02:41 IST (17 comments 348 views)
Friction Frictional resistance to the relative motion of two solid objects is usually proportional to the force which presses the surfaces together as well as the roughness of the surfaces. Since it is the force perpendicular or "normal" to the surfaces which affects the frictional resistance, this force is typically called the "normal force" and designated by N. The frictional resistance force may then be written: ffriction = &mu N &mu = coefficient of friction&muk = coefficient of kinetic friction&mus = coefficient of static friction Standard modelof friction The frictional force is also presumed to be proportional to the coefficie
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submitted by coolank2 (128 m) on 10 Aug 2007 20:19:15 IST (2 comments 227 views)
I am continuing with some more concepts.. here is a question from HCV from friction which should clear your doubts on friction. Three blocks placed on top of one another on a table.there is a 7kg block.on top of it there is a 3kg block on which there is a 2kg block.frictional coefficient between 2kg and 3kg is 0.2,that between 3kg and 7 kg is 0.3 and the table is smooth.find their accelerations when 10N force is applied on (a)2 kg block (b)3 kg block (c) 7 kg block.[g=10m/s2] a) when force acts on 2kg block: for f.b.d of 2kg block fmax= (0.2)2.10= 4N 10 - f1= 2a1 a1 = 3 ms-2 for 3kg block: f1 - f2 = 3a
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submitted by swatygupta (689 m) on 13 Jul 2007 17:35:02 IST (9 comments 300 views)
FrictionPlace a ball on a table and give it a push. The ball moves some distance and comes to rest. According to Newton's First Law, a body in motion should be in motion until and unless some external force acts on it. But in the above example, we see that though no external force is acting on the body, the ball comes to rest. According to Newton's Second Law, a retarding force must be acting on it as it moves. This force a) opposes motion, b) is always tangential to the surface in contact and c) acts in a direction opposite to the direction of motion of body. This force is called the force of friction. Thus, we define friction as an opposing
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submitted by snandkeolyar (126 m) on 29 Jun 2007 15:41:07 IST (10 comments 314 views)
The laws of friction were formulated by Leonardo da Vinci about 200 years before Newton developed the concept of force. Leonardo da Vinci wtote : 1. " Friction made by the same weight will be of equal resistance at the beginning of the movement though the contacts may be of different lengths or breadths." ( Translated into common language, it means that frictional force is independent of the area of contact. ) 2." Friction produces double the amount of effort if the weight be doubled."(It means frictional force is proportional to the normal force. And for a body re
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submitted by ramyani (2591 m) on 16 Jun 2007 00:40:28 IST (6 comments 295 views)
