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!

Work/kinetic energy problem

  1. Jul 27, 2008 #1
    I have been annoyed by a problem that I can't figure out. The topic is work and kinetic energy (chapter 6 in the sixth edition of physics for scientist and engineers by Paul A. Tipler). Problem 63 pg. 199

    A single horizontal force F acts in the +x direction on a mass m. The intial velocity is zero, the velocity is given as a function of x v=Cx where C is a contant. If the starting point x=0 and the final point is x = x' find the force and the work.

    my solution is w= .5mv^2 = .5m(Cx')^2 Therefore Fx' = .5m(Cx')^2 therefore
    F=.5mx'C^2 which is the correct answer.

    However, first I tried to do this

    f=ma = m (dv/dt) = m[C*dx/dt] = mCx' Why is this wrong???
     
  2. jcsd
  3. Jul 27, 2008 #2

    Defennder

    User Avatar
    Homework Helper

    x' in the book doesn't refer to dx/dt. It just refers to the final destination of the mass.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Work/kinetic energy problem
Loading...