1. Not finding help here? Sign up for a free 30min 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!

Work & power

  1. Dec 20, 2016 #1
    1. The problem statement, all variables and given/known data:
    Qstn no. 3.10 in the attached image.

    upload_2016-12-20_8-9-45.png
    [ Moderator note: Copy of relevant portion of attachment inserted to make it visible here]

    2. Relevant equations: For power calculation,
    Power = torque * angular velocity... Also, reduction gear is used to deliver lower outout speed at samd torque.


    3. The attempt at a solution:
    I hav tried the above equations and also correctly calculated the 1st ans(2nd attachment) but I can't calculate the 2nd and 3rd ans... I hv approached the second one but ans is not matching.. pls help... also please explain it.. as i am very weak in it...
     

    Attached Files:

    Last edited by a moderator: Dec 20, 2016
  2. jcsd
  3. Dec 20, 2016 #2

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Hello Suman, :welcome:

    why not use the same expression for b) as you use for a) ? You have ##\tau## and you have ## \omega## !
     
  4. Dec 20, 2016 #3
    Yes.. but.. what is the value uf torque here ?
    Yes I know. But how can I get the torque? If it is the resisting torque of water, then where goes the torque given by the turbine shaft ? Or will it be the difference between the above mentioned torques ?
     
  5. Dec 20, 2016 #4

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    For want of better you could start with that assumption ....
    That is a nice subject for part (c) :rolleyes:
     
  6. Dec 20, 2016 #5
    Ok I get the 2nd prt... and also the 3rd prt... thnks a lot.. but what is the significance of the 3rd part?
     
  7. Dec 20, 2016 #6

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    It's a giveaway: subtract 14.235 from 15. Too easy ! But it shows the gearbox needs cooling :smile:
     
  8. Dec 20, 2016 #7
    Yes I know the mathematical prt. I jst wanted to know to know its significance... thank you very very much.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted