Question

How do you solve this problem ?

During each heartbeat, approximately 68 cm3 of blood is
pushed from theheart at an average pressure of 105 mm-Hg. Calculate
the poweroutput of the heart, in watts, assuming 80 beats per
minute.

Answer 1

P =1.26 W

Step-by-step explanation:

number of heart beats =80 beats per minute

or, n=80(beat/60 s) = 1.33 beats /sec

volume of the blood V =68 cm^3 =
`68*10^(-6)m`

average pressure p =105 mm-Hg =110×133
`N/m^2`

(since 1 mm-Hg =133 N/m^2)

power out put is P =nW ........ (1)

where n =heart rate

work done in each heart beat is W = =pAd =pV

therefore W =pV ....... (2)

from eq (1) and (2),

P =nPV =((80/60)beats/s)(105×133 N/m^2)(68×10^{-6}m^3)

power out put P =1.26 W