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JEE Main 202224 JuneMorning Shift
Exam
JEE Main
Year
2022
Date
24 June
Shift
Morning Shift
Subject
Physics
Chapter
Rotational Motion

JEE Main 2022 · 24 June · Morning Shift · Physics · Rotational Motion

A metre scale is balanced on a knife edge at its centre. When two...

A metre scale is balanced on a knife edge at its centre. When two coins, each of mass 10g10g are put one on the top of the other at the 10.0cm10 . 0cm mark the scale is found to be balanced at 40.0cm40 . 0cm mark. The mass of the metre scale is found to be x×10−2kgx \times {10}^{- 2}kg. The value of xx is _____ .

Correct answer

0

Step-by-step solution

Let the mass of the scale be mm.

The centre of mass of the scale will be at 50cm50cm.

Applying torque balance,

0=mg×(50−40)−2×10g×(40−10)⇒m=60g=6×10−2kg0 = mg \times \left(50 - 40\right) - 2 \times 10g \times \left(40 - 10\right) ⇒ m = 60g = 6 \times {10}^{- 2}kg

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