Results 1 to 2 of 2

Math Help - Energy

  1. #1
    Member WhoCares357's Avatar
    Joined
    Feb 2009
    From
    SC
    Posts
    88

    Energy

    Each second, 1250 m3 of water passes over a waterfall 115 m high. Three-fourths of the kinetic energy gained by the water in falling is transferred to electrical energy by a hydroelectric generator. At what rate does the generator produce electrical energy? (The mass of 1 m3 of water is 1000 kg.)
    I know that E=E_p+E_k=mgd+.5mv^2. At the end of the fall there is no more potential energy so all I need is E_k=.75* (.5mv^2).

    To get v I used v=\sqrt{2gd}.

    So the final equation is E_k=.75*(mgd).

    I plugged in the numbers and got 1056562500W. According to loncapa (online system) this is wrong. Can anyone see something I did incorrectly?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,629
    Thanks
    430
    Quote Originally Posted by WhoCares357 View Post
    I know that E=E_p+E_k=mgd+.5mv^2. At the end of the fall there is no more potential energy so all I need is E_k=.75* (.5mv^2).

    To get v I used v=\sqrt{2gd}.

    So the final equation is E_k=.75*(mgd).

    I plugged in the numbers and got 1056562500W. According to loncapa (online system) this is wrong. Can anyone see something I did incorrectly?
    significant figures, maybe ?

    1.06 GW
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Generalised energy and energy (lagrangian mechanics)?
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: January 16th 2012, 03:03 AM
  2. kinetic energy during energy levels
    Posted in the Math Topics Forum
    Replies: 0
    Last Post: December 27th 2010, 01:12 AM
  3. Energy
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 19th 2009, 11:13 AM
  4. Energy
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 15th 2009, 03:30 PM
  5. Replies: 7
    Last Post: April 17th 2006, 01:04 PM

Search Tags


/mathhelpforum @mathhelpforum