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AS question I'm stuck on heeellp!

  1. Jan 26, 2004 #1
    Hi this is an AS physics question that i am stuck on. I tried it but I dont get the answer it says in the answers.

    A girl diving froma 15m plstform wishes to know how fast she enters the water. She is in the air for 1.75s and dives from rest(with an initial speed of zero). What can you tell her about her entry speed?

    I tried to do speed=distance over time
    Then I used acceleration is final velocity-initial velocity over time. But neither worked so can some1 please help me. Thanks
  2. jcsd
  3. Jan 26, 2004 #2
    Hello meawinner,

    Since Vf = Vi + a t, and the acceleration is just that of gravity, it is a simple calculation.

    Vf=Vfinal, Vi=Vinitial, a=acceleration, t=time.

    Alternately, you could us the formula Vf = Vi + sqrt(2 a d)
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