The endpin rests on the floor to help support the instruments weight.
It also has an endpin that you can pull out at the bottom of the Cello and position to the length that is suitable for you. They would sit with their legs at a 'V' with feet flat on the floor and the cello leant against their thighs. The cellist will sit down to play this instrument mainly due to its size. The cello is one of the bigger string instruments and often used for solo performances.
When music is written for the Viola it's written in alto clef which is rarely used for other stringed instruments. The Viola is more popular than many people think with Viola music writing being just as demanding as that for other stringed instruments. Because of this it is often used for solos. The Viola is slightly bigger than the Violin and plays a much deeper sound. The Violin is the smallest string instrument with the highest pitch. The sound is produced by drawing a bow across one or more strings you can also press your fingers onto the strings or pluck the strings to produce different notes. This instrument is also known as a Fiddle, the Violin has 4 strings. Strings instruments include the Violin, Viola, Cello, Double Bass and Silent Strings. The vibrations produced cause vibrations in the body and the air inside as well to make a sound. String instruments produce sound from vibrating strings, this will occur when the strings are bowed or plucked.