Final answer:
The stringed instrument that rests on the floor while played is the double bass, which uses resonance to amplify the sound from its strings.
Step-by-step explanation:
The stringed instrument that rests on the floor while being played is likely the double bass. This instrument is part of the violin family and is used in a wide range of musical genres, including orchestral music, jazz, rockabilly, and tango.
When playing the double bass, the player stands or sits on a high stool, and the body of the instrument rests on the floor. The double bass uses resonance in its sounding box to amplify the sound created by its vibrating strings, which is similar to the principle used by other stringed instruments like violins and guitars as described in FIGURE 17.27. The bridge and supports couple the string vibrations to the sounding boxes and the air within, which enriches the sound.