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!

HELP ON A WORK PROBLEM CAN'T DO IT BY MYSELF SNIFF SNIFF.:cry:

  1. Oct 6, 2006 #1
    a uniform ladder of mass 12kg is 4.6m long. if it is lifted from a horizontal to a vertical position, how much work is done

    i just thought because i have to lift the centre of the mass, i'd have to do mgh with h being 2.3m. I think i am sure that i don't have the right answer. Sniff.. help plz!:surprised :surprised
     
  2. jcsd
  3. Oct 6, 2006 #2
    I think you are correct.
     
  4. Oct 6, 2006 #3
    HAHA.... oh..... thanks.
     
    Last edited: Oct 6, 2006
  5. Oct 6, 2006 #4

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    The work must equal the potential energy increase for the ladder (since there isn't any kinetic energy relevant for this problem).

    But the potential energy increase for the WHOLE ladder, is simply the ladder's mass multiplied with g and the C.M's position, since the gravitational potential energy is linear in the vertical position coordinate.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: HELP ON A WORK PROBLEM CAN'T DO IT BY MYSELF SNIFF SNIFF.:cry:
  1. *sniff* Thanks (Replies: 4)

  2. Help! Can't do conics! (Replies: 9)

  3. Crying for help (Replies: 7)

Loading...