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: Dynamics question. inclined plane

  1. Apr 15, 2012 #1
    Hi guys

    can you help me with this question? any hint is helpful..

    an object of weight of 10 kg is to be raised 2 m off ground. there's an inclined plane for it with a freely chosen angle. How much work must be applied for the plane with 0.5 friction when after 1 m , the object its max. velocity of 1 m/s reaches? (it starts moving from 0 m/s)

    My theory: after 1m there'll be no acceleration, thus the work would be zero. everything regarding to 0 to 1 m work could be calculated by the work and energy law: W=K_2 - K_1

    the energy in the end minus the initial energy: W: 1/2 m v^2-0 = 5 J
    The F was originally the one without friction thus:

    F: 5+(FN*0.5)

    which is not correct since the result is 371.19
  2. jcsd
  3. Apr 16, 2012 #2
    Hi Raye,

    Maybe we'll have more luck if you could please post the exact text of the original question. But at a minimum, you're definitely going to need to consider the friction on the ramp; keep in mind that work = force times distance, and the whole time you are pushing against those friction forces as you slide up the ramp, as well as lifting the box. Give that some thought, and if you're still stuck please post the original text of the question and we'll try again; apologies in advance if I've misinterpreted your question,

    Hope this helps,
    Bill Mills
    Last edited by a moderator: Apr 16, 2012
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook