Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Can you feel the HEAT?

  1. May 11, 2005 #1
    hey whats up guys, I need some help solving a hw problem for physics...
    here is the question.
    A gasonline engine has a power output of 180 kW (241hp). Its thermal efficiency is 28%.

    a) How much heat must be supplied to the engine per second?
    b) How much heat is discarded by the engine per second?

    I know this is probably a simple question, but I am kind of having a hard time with this chapter. I know that thermal efficiency is equal to work/Qh...and after that...i need a little help. Thanks for any help.
     
  2. jcsd
  3. May 11, 2005 #2
    Can Anyone help? Thats all that was given in the question...
     
  4. May 11, 2005 #3

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    If only 28% of the energy supplied is converted to mechanical energy, what percent is not converted to mechanical energy? Power is just the rate of energy supplied/converted, so ask the same question about the power. Work your way back to figure out how much power must be supplied.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook