Question

The basal metabolic rate is the rate at which energy is produced in the body when a person is at rest. A 157 lb (71.0 kg ) person of height 5.91 ft(1.80 m ) would have a body surface area of approximately 1.90 m2 .
Reqiuired:
a. What is the net amount of heat this person could radiate per second into a room at 19.0 ∘C (about 66.2∘F) if his skin's surface temperature is 31.0 ∘C? (At such temperatures, nearly all the heat is infrared radiation, for which the body's emissivity is 1.00, regardless of the amount of pigment.)

b. Normally, 80.0 % of the energy produced by metabolism goes into heat, while the rest goes into things like pumping blood and repairing cells. Also normally, a person at rest can get rid of this excess heat just through radiation. Use your answer to part A to find this person's basal metabolic rate(BMR).

Answer 1

Answer:

A. Net amount of heat radiated = 109.2W

B. Person's basal energy = 136.5

Explanation:

Part A:

Area of person, A = 1.90 m^2

Temperature of person , T = 31 C

T = 304 K

Temperature of surroundings , To = 19 C

To = 282 K

Now, net amount of heat radiated = e*A*sigma *(T^4 - To^4)

Net amount of heat radiated = 1 * 1.8 * 5.6703 *10^-8 *(304^4 - 294^4)

Net amount of heat radiated = 109.2 W

The net amount of heat radiated is 109.2 W

Part B:

Person's basal energy = net amount of heat radiated /(0.80)

Person's basal energy = 109.2/0.80

Person's basal energy = 136.5 W

Person's basal energy is 136.5 W