A boy of mass 4, kg is standing on a piece of wood having mass 5 ,kg . If coefficient of fricti

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4-2.Friction

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A boy of mass $4\, kg$ is standing on a piece of wood having mass $5 \,kg$. If the coefficient of friction between the wood and the floor is $0.5,$ the maximum force that the boy can exert on the rope so that the piece of wood does not move from its place is ......$N.$(Round off to the Nearest Integer) [Take $g=10 \,ms ^{-2}$ ]

A

$25$

B

$36$

C

$45$

D

$30$

(JEE MAIN-2021)

Solution

$N + T =90$

$T =\mu N =0.5(90- T )$

$1.5 T =45$

$T =30$

Standard 11

Physics

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