1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Inclined plane and velocity

  1. Oct 24, 2004 #1
    Inclided plane


    I have a physics question.

    A block with mass m=14.7 kg slides down an inclined plane of slope angle 44.4* with a constant velocity. It is then projected up the same plane with an initial speed 2.55 m/s. How far up the incline will the block move before coming to rest?

    I know that Fnet in the x-direct (assuming x-axis is parallel to the inclined). is 0 since there is no acceleration, but constant V. Therefore Fparallel + -friction = 0. Uk = tan(44.4).

    On the way back up:
    Fnetx = ma
    Fapp + -f + -Fgx = ma
    This does not work out, as I get a to = 0.

    I need acceleration in order to find the distance travelled up the incline. Using
    Vf = Vi + 2ad

    If anyone could help me out it would be greatly appreciated.
  2. jcsd
  3. Oct 24, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    As you realize, on the way down the net force is zero. Use this fact to figure out the force of friction. Hint: On the way down, friction and gravity (the component parallel to the plane) act in opposite directions; on the way up, they act in the same direction. Use this fact to find the force and then the acceleration on the way up.

    Also: The kinematic equation you will need is [itex]v_f^2 = v_i^2 + 2ad[/itex].
    Last edited: Oct 24, 2004
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook