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Homework Help: Direction of velocity

  1. Jun 6, 2010 #1
    1. The problem statement, all variables and given/known data

    A particle is projected from the top of a vertical cliff with a speed of 40 m/s at an angle of elevation of 45 degrees towatds the sea . The particle hits the surface of the sea at a point whose horizontal distance from the cliff is 200 m . Find the direction of the velocity of the particle when it hits the surface of the sea . [Take g=10 m/s^2]

    2. Relevant equations

    3. The attempt at a solution

    For horizontal motion ,


    200=40 cos 45 t

    t=5 root (2)

    For vertical motion ,


    v=40 sin 45 -10(5 root 2)

    =-(60)/(root 2)

    This is the magnitude and i hv no idea how to find its direction
  2. jcsd
  3. Jun 6, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This gives you the vertical component of the velocity, not the magnitude. What's the horizontal component? Use the components to find the angle.
  4. Jun 6, 2010 #3
    argh , the answer is just right in front of me and i missed it . Thank you Sir .
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