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!

Latent Hear

  1. Mar 10, 2010 #1
    1. The problem statement, all variables and given/known data
    A Bullet of ice at a temperature of 0 degrees celieus is fired into a target
    Assuming that all the impact energy is retained by the ice
    what impact velocity is needed to melt 68% of the ice

    2. Relevant equations

    Q = ml
    3. The attempt at a solution
    i got..
    v^2 = 668000
    i doubt that is the correct answer
    can some show me the steps to work this out
  2. jcsd
  3. Mar 10, 2010 #2


    User Avatar
    Homework Helper

    Why didn't you use the 68%? The kinetic energy turns into the energy needed to melt 0.68m, not m.
  4. Mar 11, 2010 #3
    um im still puzzled
    can u show me the steps?
  5. Mar 11, 2010 #4


    User Avatar
    Homework Helper

    I thought you used:

    Q = ml

    and equated them to get:


    The statement 1/2mv^2=ml means "all the kinetic energy turns into the energy needed to melt the mass". However, only 68% of the mass melts, so the kinetic energy has to equal 0.68ml.
  6. Mar 11, 2010 #5
    oh i see....

    i got... 674 m/sec

    doesn't seem right

    Ek = 334800 x .68?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Latent Hear Date
Latent Heat and Entropy Nov 30, 2017
Molar latent heat of phosphine Oct 22, 2017
Sound Intensity (Level) - Hearing Aid Jul 13, 2017
Heat of Evaporation May 29, 2017