Asked by santoshwagmare67 | 26th Mar, 2021, 01:58: PM

Expert Answer:

Since the ruler is uniform , weight is acting at the centre of mass at 50 cm and balances the 40 gf
 
If we take moment of forces about fulcrum placed at 30 cm position, we get at equilibrium as
 
40 × 25 = W × 20
 
W = ( 40 × 25 ) /20 = 50 gf
 
Hence mass of scale = 50 g

Answered by Thiyagarajan K | 26th Mar, 2021, 03:39: PM