Pressure

The heart of a man pumps of blood through the arteries per minute at a pressure of of mercury. If the density of mercury is $$ $\mathrm{and}{\mathrm{}}^{}$ then the power of the heart in watts is:

A tube with both ends open to the atmosphere is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a level of above the water level on the other side. Meanwhile, the water rises by from its original level (see diagram). The density of the oil is: 

A barometer is constructed using a liquid (density = ). What would be the height of the liquid column, when a mercury barometer reads
(the density of mercury = )