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Homework Help: The pressure sand exerts on a particular area.

  1. Feb 7, 2010 #1
    Grains of sand of mass 3.0x10^-3 g each, fall from a height of 0.8 m on a sticky surface at a rate of 50 grains per second per cm^2. What pressure does this shower of sand exert on the surface, assuming that air resistance can be neglected?

    I'm really not sure what angle to take here. I believe they are trying to get me to use the equation P=F/A, however, F=ma? and F/A=mv^2(N/V).

    Am I suppose to treat this problem like an ideal gas, because the sand particles are so light?

    In addition, should i use 0.0001 m^2 for the area since it is SI units?
     
  2. jcsd
  3. Feb 8, 2010 #2

    tiny-tim

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    Hi Physics321! :smile:

    Use the full form of F = ma … F = d/dt (mv) …

    how much mv is changing per second? :wink:
     
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