Question

Following vigorous exercise, the body temperature of an 79-kg person is 41∘C. At what rate in watts must the person transfer thermal energy to reduce the body temperature to 36∘C in 26 min, assuming the body continues to produce energy at the rate of 135 W?

Answer 1

The person must transfer energy at the rate of 1021.21 W

Step-by-step explanation:

Given:

mass of the man, m = 79 klg

time, t = 26 minute

= 26 x 60

=1560 sec

Power produced by body = 135 W

Change in temperature, ΔT = 41 - 36

= 5°C

Let specific heat of man,
`c_(man)` =3500 J/kg °C

Therefore,

Heat transfer, Q = m.c.ΔT

= 79 x 3500 x 5

=1382500 J

Therefore,
`P_(cooling)` = Q / t

= 1382500 / 1560

= 886.21 W

Therefore,
`P_(requred)` =
`P_(cooling)` + power produced by body

= 886.21 + 135

= 1021.21 W

Thus, the person must transfer energy at the rate of 1021.21 W