2. An electric pump can lift a liter of water per second to a reservoir at a height h meter from ground. If the radius of the pipe through which the water is moved is b meter then calculate the velocity of water. Find the power delivered by the pump. [Neglect all resistive forces]

If the velocity of water is v then, volume of water is moved per second = area of pipe distance travelled by water per second

Or,

v = ms^{-1}.

The pump can lift the volume of water per second is a liter = cm^{3}.

Mass of the water is lifted per second is m = gram = a kg [density of water = 1 gcm^{-3}].

The potential energy per second of water due to move at a height h is E_{P} = mgh = agh joule.

The kinetic energy of water per second is E_{K} = = = joule.

Therefore the total energy of water per second is E = agh + joule.

Therefore power delivered by the pump is P = = = agh + watt.