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With what velocity did the mug leave the counter?

  1. Jun 19, 2010 #1
    1. The problem statement, all variables and given/known data
    In a local bar, a customer slides an empty beer mug down the counter for a refill. The bartender is momentarily distracted and does not see the mud, which slides off the counter and strikes the floor 1.4m from the base of the counter, If the height of the counter is 0.860m

    2. Relevant equations
    a) with what velocity did the mug leave the counter?

    3. The attempt at a solution
    I know this is a projectile motion problem
    I started and put Vy= 0 m/s and Vx= Vi
    I put the height as H= 1.4+0.860= 2.26m
    from this equation Vf=Vi-gt
    I got the time .. t=0.679s
    My idea is to ger the distance X in X direction and I have the time of the flying mug
    By dividing them I'll get the Vx which equals to the V initial of the mug
    I tried to get a relation between Vx and Vy but I failed
    can anyone help me ?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jun 19, 2010 #2
    I think you already answered the question. Yes?
  4. Jun 19, 2010 #3
    I know this is the answer but how to reach it ,,,?
    I am unable to get X in X direction I have only the time so I have an equation in two unknown
    I can't get Vx. I have no given ? So is there a way to get it ?
  5. Jun 19, 2010 #4
    You have the time its in the air. You have the distance it traveled in the x direction, why cant you get Vx?
  6. Jun 19, 2010 #5

    I don't have the distance travelled in X direction I wish I had it
    Do you have a way to get it ?
  7. Jun 19, 2010 #6
    You do have it. Read the question again. :biggrin:
  8. Jun 19, 2010 #7
    Whenever you do these types of problems you might want to do the GUESS method, and its exactly the opposite of a guess...
    G - Given: What has been given to you in the problem
    U - unknown, what are you trying to solve for
    E - equations; which equations do you have in your arsenal
    S - substitute; substitute the appropriate givens into the equations you need.
    S - Solve for the unknown.
  9. Jun 19, 2010 #8
    I don't :D
    I read it too much
    I have only the height in other words the Distance in Y direction which is 1.4+0.86
    That all I have.
    So what do u think ?
  10. Jun 19, 2010 #9
    You have to read these questions carefully sometimes and familiarize yourself with the way they are stated.:surprised
  11. Jun 19, 2010 #10
    another hint... the 0.86 is the distance the mug falls, yes?

    So make sure you remove that adding you did to get the time. They give you the distance the mug goes in the horizontal and the vertical. They are separate numbers.
  12. Jun 19, 2010 #11
    You are right
    It's solved Thank you bro :)
    So I can go and sleep now :) good night
    << he is from Egypt :D
  13. Jun 19, 2010 #12
    Good evening...
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