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Homework Help: POWER: is it possible to have the same answer?

  1. Feb 25, 2012 #1
    1. The problem statement, all variables and given/known data

    1. A 50-N force is the only force on a 2-kg object that starts from rest. when the force has been acting for 2s the rate at which it is doing work is:

    2. A 50-N force is the only force a 2-kg crate that starts from rest. At the instant the object has gone 2m the rate at which it is doing work is:

    2. Relevant equations

    3. The attempt at a solution
    Last edited: Feb 25, 2012
  2. jcsd
  3. Feb 25, 2012 #2
    I believe so but I could be wrong. I did the calculations and got what you got, the same thing, be we could both be making similar mistakes.
  4. Feb 25, 2012 #3
    hehe., thanks anyway.., :D
  5. Feb 25, 2012 #4
    anyone who can show me the solution on how to get the answer? thanks a lot guys! :D

    i have here an answer and am not sure if it's correct; for problem a, 2500watts., and for problem b 490watts.., am i correct? :)
  6. Feb 25, 2012 #5


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    Gold Member

    We don't just hand students solutions. You have to show your work. The two problems do not have the same solution.
  7. Feb 26, 2012 #6
    Man, I am just striking out.
  8. Aug 20, 2012 #7
    equilibrium temperature

    anyone who can help? this is the problem. i have the final answer which is 19.3 degree Celsius but i dunno how to get it., i used the formula of Qloss+Qgain=0;[m*c(delta T)] + [m*c(delta T)] = 0. but my final answer is not 19.3.., can you please help me? what formula will i need to use? do i need to consider the latent heat of vaporization and fusion?if so, what should be the formula?

    160grams of steam at 100 oC is added to 1000 g of ice at 0 oC. What is the equilibrium temperature of the mixture? Assume the container has a negligible heat capacity.

    thanks! :)
  9. Aug 21, 2012 #8


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    Homework Helper

    What equation relates force, mass and acceleration?

    What equation relates power (rate of doing work) to force and velocity?

    What equation relates velocity, (constant) acceleration and time?

    What equation relates velocity, (constant) acceleration and distance?

    Don't just quote the equations (we know them). Figure out how they can be applied to this problem.
  10. Aug 21, 2012 #9


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    Homework Helper

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