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QJEEM22Phfc49: JEE Main 2022 Physics - Class 11 JEEM22Phfc49 Solution: A m long ladder weighing 10 kg leans on a frictionless wall.…

A 34\sqrt {34} m long ladder weighing 10 kg leans on a frictionless wall. Its feet rest on the floor 3 m away from the wall as shown in the figure. If Ef and Fw are the reaction forces of the floor and the wall, then ratio of Fw/Ff{F_w}/{F_f} will be :

(Use g = 10 m/s2.)

JEE Main 2022 (Online) 28th June Evening Shift Physics - Rotational Motion Question 78 English

Multiple Choice Options

  • A 6110{6 \over {\sqrt {110} }}
  • B 3113{3 \over {\sqrt {113} }}
  • C 3109{3 \over {\sqrt {109} }}
  • D 2109{2 \over {\sqrt {109} }}

Step-by-Step Verified Solution

JEE Main 2022 (Online) 28th June Evening Shift Physics - Rotational Motion Question 78 English Explanation

Taking torque from B

Fw×5=32mg{F_w} \times 5 = {3 \over 2}mg

⇒Fw=310×10×10\Rightarrow {F_w} = {3 \over {10}} \times 10 \times 10

=30 N= 30\,N

N=mg=100 NN = mg = 100\,N

and fr=Fw=30 N{f_r} = {F_w} = 30\,N

so Ff=N2+fr2=10900=10109 N{F_f} = \sqrt {{N^2} + f_r^2} = \sqrt {10900} = 10\sqrt {109} \,N

so FwFf=3109{{{F_w}} \over {{F_f}}} = {3 \over {\sqrt {109} }}

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