A body weighs 82.1 gf in air, 75.5 gf in water and 73.8 gf in a liquid. A. Find the relative density of the liquid. B. How much will it weigh if immersed in a liquid of relative density 0.87 ?

Explanation

a. Given weight of the body in air `W_(1)=82.1gf`
Weight of the body in liquid `=W_(2)=73.8gf`
Weight of the body in water `W_(3)-75.5gf`
R.D. of liquid `=(W_(1)-W_(2))/(W_(1)-W_(3))`
`=(82.1-73.8)/(82.-75.5)=8.3/6.6=1.26`
b. Given R.D. of liquid `=0.87, W_(1)=82.1gf, W_(2)=?,W_(3)=75.5gf`
From relation R.D. `=(W_(1)-W_(2))/(W_(1)-W_(3))`
`0.87=(82.1-W_(2))/(82.1-75.5)`
or `82.1-W_(2)=0.87xx6.6=5.742`
`:.W_(2)=82.1-5.742=76.358`
`=76.4gf`