A real heat engine operates between temperatures Tc and Th. During a certain time, an amount Qc of heat is released to the cold
1 answer:
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Answer:
η = 40 %
Explanation:
Given that
Qa ,Heat addition= 1000 J
Qr,Heat rejection= 600 J
Work done ,W= 400 J
We know that ,efficiency of a engine given as
Now by putting the values in the above equation ,then we get
η = 0.4
The efficiency in percentage is given as
η = 0.4 x 100 %
η = 40 %
Therefore the answer will be 40%.
Answer:
The maximum height could be 10.6 meters.
Explanation:
For this kind of exercise, we use the general principle for conservation of mechanical energy (E) that states:
(1)
That means the mechanical energy an object has on a point 2 should be equal to the mechanical energy on a point 1 plus the energy transformed into heat due friction denoted as Wf (It is negative because is lost). In our case point 1 is the point where the roller coaster begins and point 2 is at the second hill. Tola mechanical energy is the sum of potential gravitational energy and kinetic energy, so (1) is :
with K the kinetic energy and U the potential energy, remember potential energy is mgh and kinetic energy is with m the mass, v the velocity and h the height, then:
Solving for h_2: