You decide to use your body as a Carnot heat engine. The operating gas is in a t

Question

You decide to use your body as a Carnot heat engine. The operating gas is in a tube with one end in your mouth (where the temperature is 37.0%u2218C) and the other end at the surface of your skin, at 30.0%u2218C.

part a

What is the maximum efficiency of such a heat engine? Would it be a very useful engine?

part b

Suppose you want to use this human engine to lift a 2.75kg box from the floor to a tabletop 1.40mabove the floor. How much must you increase the gravitational potential energy?

part c

Suppose you want to use this human engine to lift a 2.75kg box from the floor to a tabletop 1.40mabove the floor. How much heat input is needed to accomplish this?

part d

Explanation / Answer

a) e = 1 - (30+273.15)/(37+273.15)=0.0226

b) W = m g h = 2.75*1.4*9.81=37.77

c) 37.77/0.0226=1671.2

d) 1671/(350.0E3*4.184*.2)=0.0057

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