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Homework Help: Estimate the velocity achieved when you jump

  1. Sep 20, 2010 #1
    1. The problem statement, all variables and given/known data
    estimate the velocity you achieve when you jump straight up hint use the height you reach jumping on earth to estimate the change in potential energy and then use conservation of energy to estimate you initial kinetic energy

    2. Relevant equations
    ymax=(v^2 sin^2 @)/2g

    3. The attempt at a solution

    Can I just use that formula to solve for velocity or I have to use something else from what the hint is saying.
    The main question is about, seeing if you can jump off an asteroid under your own power.
  2. jcsd
  3. Sep 20, 2010 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    You have the wrong formula. Follow the hint. What is the kinetic energy and potential energy immediately after jumping (h=0, v = vmax)? What is the kinetic energy and potential energy at maximum height? Write out the expression for total energy. Does it change?

  4. Sep 20, 2010 #3
    Hey thxs for the info so this is what i got
    Pe= mgh Ke=1/2 Mv^2 height i got 50 cm mass 61235 grams and gravity is 98.1cm/s^2 (This is for astrophysics and some reason we can't use si units)

    And using conservation of energy Pei+Kei= Pef +Kef

    Pei would be 0 , we are trying to find kei Pef would be 3.00 e8 and Kef would be the same as Pef Then just solve for Kei =9e16 then plug that in the formula to find the initial velocity =1.72e6

    Did i do this right?
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