Let the mass of the scale be m.
The centre of mass of the scale will be at 50cm.
Applying torque balance,
0=mg×(50−40)−2×10g×(40−10)⇒m=60g=6×10−2kg
JEE Main 2022 — Physics Mechanics
A metre scale is balanced on a knife edge at its centre. When two coins, each of mass 10g are put one on the top of the other at the 10.0cm mark the scale is found to be balanced at 40.0cm mark. The mass of the metre scale is found to be x×10−2kg. The value of x is _____ .
Held on 24 Jun 2022 · Verified 6 Jul 2026.
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Two wires as shown in the figure below, made of steel and have breaking stress of $12 \times 10^8$ N/m$^2$. Area of cross-section of upper wire is $0.008$ cm$^2$ and of lower wire is $0.004$ cm$^2$. The maximum mass that can be added to pan without breaking any wire is _____ kg. (take $g = 10$ m/s$^2$) 
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