A block of mass M is held against a rough vertical well by pressing it with a finger. If the coefficient of friction between the block and the wall is jx and acceleration due to gravity is g, calculate the m inim um force required to be applied by the finger to hold the block against the wall.

A block of mass M is held against a rough vertical well by pressing it

1.	A block of mass M is held against a rough vertical well by pressing it with a finger. If the coefficient of friction between the block and the wall is jx and acceleration due to gravity is g, calculate the m inim um force required to be applied by the finger to hold the block against the wall.
Answer» Solution :Heremass of the block= M Coefficientof frictionbetweenthe BLOCKAND THEWALL `=mu` Lef F be forcerequiredto holdthe blockagainstthe WALL Figureshowthatweightof blockmg isindownwarddirection and frictionforce is in upwarddirectionforequilibrium f = MG F=N Frictionalforce F =`mu N` COMPARING(1) and (2) mF = Mg `F=(MG)/( mu)`