Results 1 to 4 of 4

Math Help - [SOLVED] Potential energy and conservative force?

  1. #1
    Super Member fardeen_gen's Avatar
    Joined
    Jun 2008
    Posts
    539

    [SOLVED] Potential energy and conservative force?

    The potential energy of a particle of mass 5 kg, moving in the xy plane is given by U = -7 x + 24 y J, x and y being in metres. Initially(at t = 0), the particle is at the origin and has velocity v = (14.4i + 4.2j) m/s. Then(let only conservative force be present),

    A) Speed of the particle at t = 4 s, is 25m/s
    B) the acceleration of the particle is 5m/s^2
    C) the direction of acceleration of the particle is perpendicular to its direction of motion, initially
    D) the direction of acceleration of the particle is along the direction of motion initally.

    More than one options may be correct.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by fardeen_gen View Post
    The potential energy of a particle of mass 5 kg, moving in the xy plane is given by U = -7 x + 24 y J, x and y being in metres. Initially(at t = 0), the particle is at the origin and has velocity v = (14.4i + 4.2j) m/s. Then(let only conservative force be present),

    A) Speed of the particle at t = 4 s, is 25m/s
    B) the acceleration of the particle is 5m/s^2
    C) the direction of acceleration of the particle is perpendicular to its direction of motion, initially
    D) the direction of acceleration of the particle is along the direction of motion initally.

    More than one options may be correct.
    Note that F = - \nabla U \Rightarrow a = - \frac{\nabla U}{5}.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member fardeen_gen's Avatar
    Joined
    Jun 2008
    Posts
    539
    Is that the del operator?(as in d/dr r)?

    I tried this:

    F = -(∂/∂x U i + ∂/∂y U j)
    = -(-7i + 24j)
    = 7i - 24j

    Am I correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by fardeen_gen View Post
    Is that the del operator?(as in d/dr r)?

    I tried this:

    F = -(∂/∂x U i + ∂/∂y U j)
    = -(-7i + 24j)
    = 7i - 24j

    Am I correct?
    Yes.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Conservative force
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 28th 2011, 05:45 AM
  2. gravitational potential energy
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: November 10th 2009, 08:02 PM
  3. Single particle with conservative force
    Posted in the Advanced Applied Math Forum
    Replies: 3
    Last Post: June 29th 2009, 09:43 AM
  4. conservative force field
    Posted in the Calculus Forum
    Replies: 0
    Last Post: May 3rd 2009, 05:16 AM
  5. potential energy
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: January 6th 2009, 03:53 AM

Search Tags


/mathhelpforum @mathhelpforum