The heart of a man pumps 4000 cc of blood through the arteries per minute at a pressure of 130 mm Hg. If the density of mercury is 13.6×103 kg/m3, what is the power of heart ?
The heart of a man pumps 4000 cc of blood through the arteries per minute at a pressure of 130 mm Hg. If the density of mercury is 13.6×103 kg/m3, what is the power of heart ?
The correct option is A 1.15 watt
We know that power is equal to rate of doing work. In the given configuration, we can consider that the given volume of blood has been raised up by a certain height, whose equivalent height in terms of mercury is 130 mm. Thus power can be calculated by equating it to rate of increase of potential energy of the equivalent mercury column (instead of blood column).
Thus calculation can be done by using the formula, P=mght
Now, here mass of 4000 c.c. of mercury should be calculated, as in equivalent terms, the work done in pushing 4000 c.c. of blood to a certain height which is not given in the problem is same as the work done in pushing the same volume of mercury to a height of 130 mm.
P=mght=d×V×g×h/t
=4000×10−6×13.6×103×9.8×0.13/60=1.15 watt
We know that power is equal to rate of doing work. In the given configuration, we can consider that the given volume of blood has been raised up by a certain height, whose equivalent height in terms of mercury is 130 mm. Thus power can be calculated by equating it to rate of increase of potential energy of the equivalent mercury column (instead of blood column).
Thus calculation can be done by using the formula, P=mght
Now, here mass of 4000 c.c. of mercury should be calculated, as in equivalent terms, the work done in pushing 4000 c.c. of blood to a certain height which is not given in the problem is same as the work done in pushing the same volume of mercury to a height of 130 mm.
P=mght=d×V×g×h/t
=4000×10−6×13.6×103×9.8×0.13/60=1.15 watt
