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: Block on a wedge

  1. Feb 18, 2010 #1
    1. The problem statement, all variables and given/known data
    http://uploadpie.com/7kzGG [Broken]


    2. Relevant equations



    3. The attempt at a solution
    The correct answer is A : 0N
    But my answer is B : 12 N
    Here is my attempt

    http://uploadpie.com/UUGwM [Broken]

    I know I can consider the block and the wedge as one system and I can get the correct answer. But I want to know what's wrong with this approach.
    Thanks for help
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 18, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi zohapmkoftid! Welcome to PF! :smile:
    Yes, Rsinθ is the horizontal component of the normal component of the reaction force

    But you haven't included the whole reaction force …

    what about the friction component? :wink:
     
  4. Feb 19, 2010 #3
    Yes, I haven't considered f cos
    thank you!!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook