Explain why bullets of a gun are cylindrical in shape.

$A$ liquid is kept in a cylindrical vessel. When the vessel is rotated about its axis,the liquid rises at its sides. If the radius of the vessel is $0.05\, m$ and the speed of rotation is $2$ revolutions per second,the difference in the heights of the liquid at the centre and at the sides of the vessel will be ...... $cm$. (Take $g = 10\, ms^{-2}$ and $\pi^2 = 10$)

What is fluid statics? $OR$ What is fluid mechanics?

$27$ equal small water drops combine to form a big drop. If the surface tension of water is $T$ and the radius of a small drop is $r$,then:
$(A)$ The excess pressure inside the big drop is three times the excess pressure inside the small drop.
$(B)$ Surface energy decreases in this process.
$(C)$ In this process,$72 \pi r^2 T$ energy is released.
$(D)$ The radius of the big drop is $3r$.
The true statements are:

State whether the following statements are True or False:
$(i)$ The Bernoulli equation can be considered to be a statement of the conservation of energy.
$(ii)$ The angle of contact between a drop of water and the material of a raincoat is an acute angle.
$(iii)$ The absence of roughness between two consecutive layers of fluid is the definition of viscosity.

The figure shows a three-arm tube in which a liquid is filled up to a height $l$. It is now rotated at an angular frequency $\omega$ about an axis passing through arm $B$. Find the angular frequency $\omega$ at which the level of liquid in arm $B$ becomes zero.