Question

A solid lighter than water is found to weigh 7.5 gf in air. When tied to a sinker the combination is found to weigh .If the sinker alone weighs 72.5 gf in water, find R.D. of solid.

Answer 1

Weight of solid in air = 7.5 gf
Weight of sinker in water = 72.5 gf
Wt. of sinker in water + Wt. of solid in air
= 72.5 + 7.5 = 80.0 gf …(1)
Wt. of solid in water + Wt. of sinker in water = 62.5 gf …(2)
Subtract eq. (1) from eq. (2)
Wt. of solid in air – Wt. of solid in water = 80- 62.5 = 17.5 gf.

∴ R.D. of solid = `"Weight of solid in air"/("Wt. of solid in air" - "Wt. of solid in water")`

`= 7.5/17.5 = 0.428`