Carnot engine rejected heat problem

AI Thread Summary
The discussion revolves around solving a problem involving two Carnot engines, A and B, where engine A takes in 5550J of heat and delivers 1750J of work, rejecting heat to a cold reservoir at 503K. The main question is determining the input heat for engine B, which is derived from the rejected heat of engine A. The conservation of energy principle is emphasized, indicating that the input energy must equal the sum of work done and heat rejected. The user calculated T1 as 734.3K but is unsure how to proceed without knowing the input heat for engine B. Clarification on energy conservation and the relationship between the two engines is needed to solve for T2.
Nimbalo
Messages
2
Reaction score
0

Homework Statement


From the hot reservoir at a temperature of T1, Carnot Engine A takes an input heat of 5550J, delivers 1750J of work and rejects heat to a cold reservoir that has a temperature of 503K. This cold reservoir also serves as the hot reservoir for a second Carnot Engine, B, which uses the rejected heat from the first engine as input heat. Engine B also delivers 1750J of work, while rejecting heat to an even colder reservoir that has a temperature T2. Find T1 and T2.


Homework Equations


e=1-Tc/Th
e=W/Qh


The Attempt at a Solution



I plugged in my values into the e=1-Tc/Th and e=W/Qh equations to solve for the Th, or T1. As an answer, I got 734.3K. However, I'm missing a variable for my second Carnot engine. What is the input heat for engine B? I tried doing 734.3-503K, but that gives me answers in K and makes the equation not work. I don't know what I'm supposed to use for the input heat.
 
Physics news on Phys.org
Welcome to PF :smile:

Nimbalo said:
What is the input heat for engine B?

It's the same as the output heat from engine A:
... a second Carnot Engine, B, which uses the rejected heat from the first engine as input heat.

Engine A has 5550 J of input heat. Of that 5550 J energy, 1750 J is used to do work. The remaining energy has to go somewhere (conservation of energy) ...
 
so what does this mean? what do i do with the conservation of energy?
 
copitlory8 said:
what do i do with the conservation of energy?
Equate the input energy with the total output energy.
Qin = W + Qout
If you need more help with the problem, you will have to show how far you have gotten and the work you have done.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top