Question

The power of the heart which beats 72 times in a minute is 1.2 KW. Calculate the work done by the heart for each heartbeat.

Answer 1

In this type of question, first we know about what the question asked then we know about the heart beat which beats 72 times in a minute. After the age of 10 years, the heart rate of a person should be between 60 and 100 beats per minute while they are resting.then we use the formula of power = $\dfrac{{Work\;done}}{{Time\;taken}}$ to proceed this question.

Complete step by step answer:
We Know that,
Power = $\dfrac{{Work\;done}}{{Time\;taken}}$
Now,
Work done = Power × Time taken
Given. Power of the heart = 1.2 KW
= 1.2 × 1000 W
= 1200 W.
Time taken = 1 minute = 60 second.
We know the formula of work done related to power.
Work done = Power × Time taken
Use the above given data
Work done = 1200 × 60
= 72000 J.
Now,
Work done to beat 72 times = 72000 J.
Work done to beat 72 times = 72000 J.
Work done to beat 1 times = $\dfrac{{72000}}{{72}}$
= 1000 J
= $= \dfrac{{1000}}{{1000}}KJ$
= 1 KJ.
Hence,

Work done to beat 1 time is 1 KJ.

Note: In this type of question, first we know about what the question asked then we know about the heart beat which beats 72 times in a minute. After the age of 10 years, the heart rate of a person should be between 60 and 100 beats per minute while they are resting, and we always use the unit of work done in joule or kilojoule and time in second. We know about the power formula Power = $\dfrac{{Work\;done}}{{Time\;taken}}$ then proceed to solve it.