A student eats 2100 kcal per day Problem. Please Help me on this problem.?

Question

A student eats 2100 kcal per day.

(a) Assuming that all of the food energy is released as heat, what is the rate of heat released? (Recall that 1 W = 1 J/s.)
_______W

(b) What is the rate of change of entropy of the surroundings if all of the heat is released into air whose temperature is 4°C?
_______W/K

Answer 1

(a)
1 calorie = 4.184 joules, so 2100 kilocalories = 8,786,400 joules.
1 day = 86,400 seconds.
So, releasing 2100 kilocalories over one day means your rate of heat release is:
(8,786,400 joules) / (86,400 seconds) = 101.7 watts

(b)
The formula for entropy change is
dS = dQ / T
dS = 1/T * dQ
So, the RATE of entropy change is
dS/dt = 1/T * dQ/dt
dS/dt = 1/(4 celsius) * (101.7 watts)
dS/dt = 1/(277.15 kelvin) * (101.7 watts)
dS/dt = 0.3669 W/K