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: Conservative force, kinetic energy

  1. Oct 18, 2009 #1
    1. The problem statement, all variables and given/known data
    A single conservative force F(x) acts on a 2.4 kg particle that moves along an x axis. The potential energy U(x) associated with F(x) is given by
    U(x) = -4xe-x/4
    where x is in meters. At x = 5.0 m the particle has a kinetic energy of 5.2 J. (a) What is the mechanical energy of the system? (b) What is the maximum kinetic energy of the particle and (c) the value of x at which it occurs?

    2. Relevant equations

    3. The attempt at a solution
    I know how to find the mechanical energy, but I don't know how to do the derivative of U(x) so that I can do b) and c) even though its simple.
  2. jcsd
  3. Oct 18, 2009 #2
    this should be enough to find it

    the derivative of e^x is e^x
    the derivative of f(x)g(x) = f'(x)g(x) + f(x)g'(x)
    the derivative of f(g(x)) = g'(x) f'(g(x))
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook