A body B lies on a smooth horizontal table and another body A is placed on B . coefficient of fricti

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4-2.Friction

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A body $B$ lies on a smooth horizontal table and another body $A$ is placed on $B$. The coefficient of friction between $A$ and $B$ is $\mu $. What acceleration given to $B$ will cause slipping to occur between $A$ and $B$

A

$\mu g$

B

$g/\mu $

C

$\mu /g$

D

$\sqrt {\mu g} $

Solution

(a) There is no friction between the body $B$ and surface of the table. If the body $B$ is pulled with force $F$ then $F = ({m_A} + {m_B})\,a$

Due to this force upper body $A$ will feel the pseudo force in a backward direction.

$f = {m_A} \times a$

But due to friction between $A$ and $B$, body will not move. The body $A$ will start moving when pseudo force is more than friction force.

i.e. for slipping, ${m_A}a = \mu \;{m_A}g$

$\therefore a = \mu \,g$

Standard 11

Physics

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