QUESTION FOUR

a$.$ Derive expressions from basics for the pressure inside a droplet and a free jet.

$(12$marks$)$

b$.$ Determine the diameter of a spherical balloon at an altitude where pressure and

temperature are $0\mathrm{.}1$ bar and $-50C,$ if $5\mathrm{.}65$ kg of hydrogen was charged into the

balloon at ground level where the pressure and temperature were $1$ bar and $30C.$

$(7$marks$)$

c$.$ Bubbles are to be blown using a glass tube of $2$ mm diameter immersed in oil to a

depth of $10$ mm $.$ The specific gravity of oil is $0\mathrm{.}96.$ If the surface tension of the oil is

$0\mathrm{.}0389\frac{N}{m}.$ Determine the pressure inside the bubble at formation. $(6$ marks $)$