Acceleration of gravity calculation on the surface of a planet. It's possible to calculate the acceleration above the surface by setting the sea level. But it won't be possible under thesurface - this is a wrong formula.

- Hydrostatic pressure
This online calculator can solve hydrostatic pressure problems by finding unknown value in hydrostatic equation.

- Surface tension. Weight and volume of the drop of liquid
This online calculator calculates the weight and the volume of the drop given the surface tension, diameter of the capillary tube, and density of the liquid