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!

Frictionless inclined plane physics homework

  1. Nov 20, 2005 #1


    User Avatar

    A 2.0 kg mass slides down a frictionless inclined plane that makes an angle of 30 degrees with the horizontal. The sass starts from rest. What is its speed after it has slid a distance of 3.0 m along the incline?

    I got:

    F = (sin30)(9.8)
    F = 4.9 N

    W = Fd
    W = (4.9) (3) = 14.7 J

    W = E_kin
    14.7 J = 1/2 mv^2
    v = 1.21 m/s

    Is my method correct? I'm very unsure how to do this one. Thanks.
  2. jcsd
  3. Nov 20, 2005 #2


    User Avatar
    Homework Helper

    your Work-Energy method is excellent ...
    but a few chapters ago, F = M g sin (theta)
    . . . if you had USED units [kg N/kg] you would have caught your error.
  4. Nov 20, 2005 #3


    User Avatar

    F = M g sin (theta) ?

    I'm not sure what you mean. :confused:
  5. Nov 21, 2005 #4


    User Avatar
    Gold Member

    you forgot the mass when you calculated the force.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Frictionless inclined plane physics homework