Question

A uniform meter scale is kept in equilibrium when supported at the 60 cm mark and a mass M is suspended from the 90 cm mark as shown in the figure. Which of the following is true?

• A. The weight of the scale is equal to the weight of mass m
• B. The weight of the scale is less than the weight of mass m
• C. The weight of the scale is greater than the weight of mass m
• D. cannot be said from the given data

Answer 1

The correct option is C

The weight of the scale is greater than the weight of mass m

Weight (say 'w') of the meter scale will be acting at its mid-point, i.e., at 50 cm mark.

Therefore, by the principle of moments,

w x (60-50) cm = Mg x (90-60) cm

or, 10 w = 30 Mg

or, w = 3 Mg

Therefore, weight (w) of the scale is greater than the weight of the suspended mass m.