In an experimental study designed to simulate the manner in which a cat drinks, a glass plunger simulating a cat's tongue just makes contact with the free surface in a pan of water. The plunger then oscillates vertically, causing a column of water to rise and eventually be pulled back down by gravity. The oscillation frequency, w(omega), depends upon surface area of the plunger, A, plunger velocity, U, acceleration of gravity, g, water density, p(roh), and surface-tension coefficient (sigma). How many dimensionless grouping are there? What are the dimensionless groupings?