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## Homework Statement

Grains of sand of mass 3.10 10-3 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?

## Homework Equations

P=F/A

F=ma=mv d/dt

## The Attempt at a Solution

So I understand I have to calculate the velocity and multiply that by the mass and number of grains. What I don't understand is the area. What is the area? Any help would be great.