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Question
A body slipping on a rough horizontal plane moves with a deceleration of 4.0 m/s2. What is the coefficient of kinetic friction between the block and the plane?
Solution
Let m be the mass of the body.
From the free body diagram,
R − mg = 0
(where R is the normal reaction force and g is the acceleration due to gravity)
⇒ R = mg (1)
Again ma − μkR = 0
(where μk is the coefficient of kinetic friction and a is deceleration)
or ma = μkR
From Equation (1),
ma = μkmg
⇒ a = μkg
⇒ 4 = μkg
`=>muk=4/g=4/10=0.4`
Hence, the coefficient of the kinetic friction between the block and the plane is 0.4.
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