Question
Mon September 05, 2011 By: Venika Singhal
 

When object is allowed to slide down a hill from point A on top it stops at the point B,because of friction. If friction force depends only on normal component of the reaction for which coefficient of friction varies along the path. What is work done in taking the object slowly from B to A along the hill.

Expert Reply
Mon September 05, 2011
Frictional forces are proportional to the forces which presses the surfaces . The force which will affect frictional resistance is the component of applied force which acts perpendicular or "normal" to the surfaces which are in contact and is typically referred to as the normal force.
The normal force is just the weight of the object which is sitting on some surface.
If friction force depends only on normal component of the reaction for which coefficient of friction varies along the path then work done in taking the object slowly from B to A along the hill will be equal to the weight of object.
 
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