Question

A stone weighs 650 N in air and 275 N in water. Compute its specific gravity.

(a) 1.73

(b) 2.45

(c) 3.46

(d) 0.865

I have been asked this question in examination.

My question is from Bouyancy topic in chapter Buoyancy and Floatation of Fluid Mechanics

Answer 1

Right option is (a) 1.73

To explain I would say: Weight of water displaced=Weight of stone in air – Weight of stone in water

                                                             =375

Volume of water displaced=Volume of stone=375/9.81*1000=0.038 m3

 Density of stone= mass/volume=650/9.81*0.038=1733 kg/m^3

specific gravity= Density of stone/Density of water=1.73.