Exercise 1

1. Water

2. Oil of specific gravity 0.8

3. Mercury of specific gravity 13.6.

Solution: Height of liquid column h' = 0.5 m

S _oil = 0.8
S _mercury = 13.6
Density of water ( ?) = 1000 kg/m ³
Gravitational force ( g) = 9.8 m/s ²

1. We know according to hydrostatic law that pressure developed in a fluid due to a height h' is given by

   
   

   ? Pressure due to a column of 0.5 m of water = 4900 N/m ² (SI units) [In metric units = 4900/9.8 100 100 = 0.05 kg/cm ² (where 9.81 is to convert Newton into kgf and 100 100 is to convert m ² into cm ²).]

2. Pressure due to oil column: P _(oil) = ? _(oil) gh We know,

   
   

   Pressure due to oil column = 3920 N/m ².

3. Pressure due to mercury column: P _(mercury) = ? _(mercury) gh

   
   

   Pressure due to mercury column = 66 640 N/m ².

1. Water

2. Oil of specific gravity is 0.9.

Solution: P = 4 N/cm ² = 40 000 N/m ²
S _oil = 0.9
? _water = 1000 kg/m ³