- #1
twinklestar28
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Homework Statement
A heat engine operating between freezing and boling points of water takes 20 cycles to raise a mass of 1000kg through a height of 3m. Calculate the minimum energy per cycle that must be extracted from the hot reservoir in order to achieve this.
Homework Equations
η=1-Tc/Th
η=W/Qh
P.E=mgh
The Attempt at a Solution
I assumed that the acceleration woas 9.81m/s^2 so I got 2943J for the Work done and then divided by 20 to get the energy for one cycle to get 147.15J. Plugging into the equation i got Qh= 525.5J which doesn't seem to sound right considering the question is worth 4 marks.Can i assume that the GPE of the mass is the work done or is there more to it? Do I need to include Qc in the work done (WD=Qh-Qc)?
Thanks for any help :)