a bkock placed on a rough inclined plane of length 4m just begins to slide down when the upper end of the plane is 1m high from the ground.calculate the coefficient of static friction.

Answer 1

the angle of the board is arcsin(.25)

mu=tangent(arcsin(.25))

force down the plane=mgSinTheta
force normal: mgCosTheta
friction up plane: mg*mu*cosTheta

movement occurs when force down >friction or
mgSinTheta=>mg*mu*CosTheta or

mu=TanTheta