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?