Question

A uniform metre rule which has a mass of $75g$ is suspended by a thread at the $75cm$ mark and is balanced by a mass of weight W hanging from the $90cm$ mark. Calculate the value of W.

• A. 75 g
  
• B. 125 g
  
• C. 150 g
  
• D. 250 g
  

Answer 1

The correct option is B 125 g

from Equilibrium,

clockwise moment=anticlockwise moment

$W\times 15=75\times g\times 25$

$m\times g\times 15=75\times g\times 25$

$\therefore =\frac{75\times 25}{15}=125g$