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!

Conservation of Energy

  1. Apr 4, 2009 #1
    1. The problem statement, all variables and given/known data


    box.jpg
    2. Relevant equations
    Wgravity = mgh
    KE=1/2mv2



    3. The attempt at a solution

    I know the gravitational potential energy is different because mgh accounts for mass.
    But the book says that B is correct. I don't know why because isn't the less mass you have the faster you go? 2KE/m=v2
     
  2. jcsd
  3. Apr 4, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    Step back a bit and look at the equations.

    PE = KE at the bottom.

    m*g*h = 1/2*m*v2

    v2 = 2*g*h

    The mass has canceled out.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook