Question

In each heartbeat, a heart pumps 90ml of blood at an average pressure of 200 mm of Hg. What will be the power output of the heart? (Assume 60 heartbeats per minute)

Answer 1

Hint: We all know that beating of the heart is nothing pumping blood too. On a single beat, blood from the heart gets pumps. That blood exerts a pressure known as blood pressure which we generally measured in 200mm of Hg. Work done is nothing but pressure into volume. While power is equal to work done per unit time.

Complete answer:
We all know that our heartbeats. Within 1 minute, if our heart beats 72 times then we consider our heart is healthy and blood flow is also regular.
So in this question, it is given that, in each heartbeat, heats pump 90ml of blood at an average pressure of 200 mm of Hg
We know that work done is nothing but pressure into volume.
Mathematically.
W=pdv
Where, $dV=60\times (90\times {{10}^{-6}})=5400\times {{10}^{-6}}$
We have pressure given by 200 mm of Hg. To convert it into pascal, we get
$P=\dfrac{200}{760}\times {{10}^{5}}\times 101Pa=2.66\times {{10}^{4}}Pa$
Noe rearrange work done equation, we get,
$power=\dfrac{work done}{time}$
$power=\dfrac{2.66\times {{10}^{4}}\times 60\times 90\times {{10}^{-6}}}{60\sec }=2.31W$
So this is our answer.

Note:
While solving the question, first understand what question you want to convey. Always try to make a picture of the question. Like that it will be easy to guess the solution. We have to ask about power. And we know that there is a relation between power and work. So try to get this relation. Automatically formula will get click on your head