Pressure is force over area. So assuming your cube is at rest and on earth, then the force is mass x gravity and the pressure is mass x gravity / area.
A string quartet is made up of four musicians playing two violins, a viola, and a cello. These are all string instruments played either by plucking the strings or using a bow. The violins are the smallest and typically play the higher notes. The viola and cello are larger instruments and play the lower notes.
There are four instrument families: the string, woodwind, brass and percussion family. The string family has instruments that, like its family name, has strings. In an orchestra, the most common string instruments are the violin, viola, cello and the double bass.