Q 4. A guitar string can be simply considered as a 650mm long section of 0.6mm diameter steel cable rigidly fixed at its endpoints. If the string is relaxed (taut but zero stress/strain) at a room temperature of 20C and taken to an outdoor winter concert on a chilly 15C day, what will be the magnitude of thermally induced stress? Will the cold guitar string be in tension or compression? Explain (briefly)