Question

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

• A. $W$ = w
• B. $W$ < w
• C. $W$ > w
• D. Data insufficient

Answer 1

The correct option is C

$W$ > w

Weight (let $W$) of the meter scale will be acting at its mid-point, i.e., at $50cm$ mark.

Therefore, by the principle of moments: $W\times (60-50)cm=w\times (90-60)cm$or $10W=30w$
or $W=3w$

Therefore, weight $W$ of the scale is greater than the weight $w$ of the suspended mass m.