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Homework Help: Energy obtained from peanuts

  1. Oct 10, 2012 #1
    1. The problem statement, all variables and given/known data
    How much energy can we obtain from 211g of peanuts. (Remember c = speed of light = 3 E 8 m/s) Remember to write your answer to two decimal places and for example 4.56x10^8 must be written as 4.56E8

    2. Relevant equations
    E = mc2
    c = 300,000,000 m/sec

    3. The attempt at a solution
    211 g = 0.211 kg
    E = (0.211)(300,000,000)2
    E = 7.21899e+18

    Energy = 7.22E18 Joules

    Am I correct??
    Last edited: Oct 10, 2012
  2. jcsd
  3. Oct 10, 2012 #2


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    Hi Hannah1! :smile:
    You seem to have entered 80.211 into your calculator. :wink:
  4. Oct 10, 2012 #3
    You're right! My bad. I tried again and this is what I got:
    E = (0.211)(300,000,000)2
    E = 1.899e+16

    Therefore, Energy = 1.90E16 Joules.

    Am I correct now??
  5. Oct 11, 2012 #4


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    (just got up :zzz:)
    he he :biggrin:

    yes :smile:
  6. Oct 11, 2012 #5
    Thank you! :smile:
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