An engine does 10 j of work and exhausts 25 j of waste heat during each cycle.
what is the thermal efficiency?
i did it like
eff = = 0.67 = 67%
but my homework said it was incorrect
so i tried it this way
eff = = 0.4 = 40%
but that is also incorrect, so what am i doing wrong?

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.

Individuals who live below the poverty line get seriously ill more often than those who do not what could be the hidden variable in this situation?

The heliocentric and the geocentric models of the solar system included these central principles