1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Average Power Output

  1. Sep 28, 2013 #1
    1. The problem statement, all variables and given/known data

    620 seconds after starting its take-off, a 260000 kg jet reaches its cruising altitude of 9200 meters and flies with a speed of 235 m/s. Neglecting friction, what has been the average power output of the engines?

    2. Relevant equations

    ΔKE = Work
    Power = Work/time

    3. The attempt at a solution

    Initial KE = 0
    Final KE = .5*260000*235^2 = 7179250000
    Power = 7179250000/620 = 11579435.48 Watts

    Can someone see an issue with what I am trying to do here? I tried to type in this answer but apparently it is wrong.
  2. jcsd
  3. Sep 28, 2013 #2


    User Avatar
    Gold Member

    I haven't checked your math, but I can see you left out the change in potential energy.
  4. Sep 28, 2013 #3
    Ok. Would that go into the work equation?
  5. Sep 29, 2013 #4


    User Avatar
    Gold Member

    I believe so.

    Try this: ΔKE + ΔPE = Work

    and see what happens.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted