A mercury drop shaped as a round tablet of radius R and thickness h is located between two horizontal glass plates. Assuming that h << R, find the mass m of a weight which has to be placed on the upper plate to diminish the distance between the plates n-times. The contact angle equals 0. Calculate m if R = 2.0 cm, h = 0.38 ram, n = 2.0, and θ = 135 °.