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.
Compare these retailers... The string quartet is to chamber music what the symphony is to the orchestra: the most popular and prestigious form. A string quartet is written for two violins, a viola, and a cello, and typically has four movements.