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Rocks thrown off cliff

  1. Dec 3, 2009 #1
    1. The problem statement, all variables and given/known data
    A person climbs 50m cliff that overhangs calm pool of water. He throws two stones vertically downward, 1s apart, and observes that they cause a single splash. The first stone has an initial speed of 2m/s downward.

    (a) How long after release of the first stone do the two stones hit the water?
    (b) What initial velocity must the second stone have if they are to hit simultaneously?
    (c) What is the speed of each stone at the instant the two hit the water?

    2. Relevant equations
    Probably big 6 mechanics. We will have to calculate how long it takes the first stone to hit water then subtract one to get part a.
    Once we figure out T we can probably figure out part b.
    Not sure about part c.
  2. jcsd
  3. Dec 3, 2009 #2


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    For part c, once you have the time of flight for each stone, just use the kinematic equation giving the velocity at any time t to find the final speed of each stone.
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