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: Uh Hi help me please?

  1. Oct 9, 2008 #1
    1. The problem statement, all variables and given/known data
    A jet engine gets it thrust by taking in air, heating and compressing it, and then ejecting it at a high speed. IF a particular engine takes in 20 k/g of air per second at 100 m/s and ejects it at 500 m/s calculate the thrust of the engine.
    chriss #getmoney: thrust of the engine would be v right?

    2. Relevant equations

    i believe that the equation is Mv1 + Mv2 = V(Mv1+Mv2) and that the thrust = V .

    3. The attempt at a solution
  2. jcsd
  3. Oct 11, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Thrust is a force rather than velocity.

    Hint: Try using Newton's Second Law.

    Edit: The equation that you have written doesn't make sense, it simplifies to V=1 for all M and v.
    Last edited: Oct 11, 2008
  4. Oct 11, 2008 #3


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi chrishere?! Welcome to PF! :smile:

    Thrust is a force, so use Newton's second law in the form force = rate of change of momentum.

    How much momentum is being ejected? :wink:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook