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!

Force On an Inclined Plane

  1. Sep 23, 2008 #1
    1. The problem statement, all variables and given/known data


    A 50 kg block on a frictionless inclined plane experiences a horizontal force. The plane is inclined at 30 degrees.

    a- If the block moves up the ramp with a constant velocity, find the magintude of 'F'.
    b- Suppose the block accelerates up the ramp at 0.5 m/s^2. Find 'F' now.

    2. Relevant equations

    EF = ma...?

    3. The attempt at a solution

    I drew a diagram with F going left on the x, nx going right on the x, ny going up on the y, and w going down on the y.

    Do I need to find a maginitude for the normal force? How can I do that? I believe nx = F and ny = w, but where do I go from there, if that's even correct?
     
    Last edited: Sep 23, 2008
  2. jcsd
  3. Sep 23, 2008 #2
    What is nx and ny and w?


    You should resolve the Weight into x and y components, not the normal force.
     
  4. Sep 23, 2008 #3
    w = weight, nx and ny are the components of the normal force, which I drew pointing up perpendicular to the plane. I didn't think I needed two components for the weight, since it is pointing straight down?
     
  5. Sep 23, 2008 #4

    LowlyPion

    User Avatar
    Homework Helper

    The inclined plane separates the force of gravity which is straight down insofar as looking at kinematics on the plane.

    The Normal force is perpendicular to the plane. Horizontal force is along the plane. That means the Normal force is M*g*Cosθ The force down the incline is mg*Sinθ .

    So what value of F would leave the block in constant motion? (Hint: no net horizontal force along the incline.)

    Note when I say horizontal I mean horizontal along the incline. If the force is horizontal along the plane that the incline is on, then that would be different.
     
  6. Sep 23, 2008 #5
    The way I drew it is the only way I've been shown. To make it clear, the force IS parallel to the plane that the incline is on, not to the plane.
     
    Last edited: Sep 23, 2008
  7. Sep 23, 2008 #6

    LowlyPion

    User Avatar
    Homework Helper

    Well that makes it simpler then.
     
  8. Sep 23, 2008 #7
    OK, so back to the original question...

    Do I need to find a maginitude for the normal force? How can I do that? I believe nx = F and ny = w, but where do I go from there, if that's even correct.
     
  9. Sep 23, 2008 #8

    LowlyPion

    User Avatar
    Homework Helper

    As long as there is no friction you don't need that force. What ever it is the plane pushes back.
     
  10. Sep 23, 2008 #9
    I thought I needed that because the normal force's x component is opposite the F force in the diagram. If not, what do I need?
     
  11. Sep 23, 2008 #10
    what is the point of finding the magnitude of the normal force.
     
  12. Sep 23, 2008 #11
    If there is no point to finding the normal force, could someone please explain to me how to solve this?
     
  13. Sep 23, 2008 #12
    ok I think You have to make tow formulas let me give you litle hint
    The force in the X- direction will be F - cos(teta) mg = ma
    DONT forget the velocity is constant.

    and Force in the Y- direction is N - sin(teta)mg = ma
    Dont forget the acceleration would be zero.
     
  14. Sep 23, 2008 #13
    Alright. Thanks for helping!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Force On an Inclined Plane
Loading...