A block A with mass 100, kg is resting on another block B of mass 200, kg . As shown in figure a hor

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4-2.Friction

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A block A with mass $100\, kg $ is resting on another block $B$ of mass $200\, kg$. As shown in figure a horizontal rope tied to a wall holds it. The coefficient of friction between $A$ and $B$ is $ 0.2 $ while coefficient of friction between $B$ and the ground is $0.3$. The minimum required force $F$ to start moving $B$ will be ........ $N$

A

$900$

B

$100$

C

$1100$

D

$1200$

Solution

(c) $F = {f_{AB}} + {f_{BG}}$

$ = {\mu _{AB}}{m_a}g + {\mu _{BG}}({m_A} + {m_B})g$

$ = 0.2 \times 100 \times 10 + 0.3(300) \times 10$ $ = 200 + 900 = 1100\;N$

Standard 11

Physics

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(JEE MAIN-2019)