Q8 of 11 Page 83

The heat of a health person beats 72 times per minute and each beat uses up about 1J of energy. Calculate the power of the heart.

Power is defined as time taken by an object to do the work. Or we can also say rate of doing work.

Mathematically,



which implies,


So, according to question the heart beats 72 times and each time it uses 1 Joule energy.


Hence, total work done by heart in one minute = 72 × 1


= 72 J


Time taken by heart to beat 72 times = 1 min = 60 s


Power = 72 / 60


= 1.2 J/s


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