Why is tubing sometimes coiled when installed in a car or vechile

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Steam enters a converging nozzle at 3.0 mpa and 500°c with a at 1.8 mpa. for a nozzle exit area of 32 cm2, determine the exit velocity, mass flow rate, and exit mach number if the nozzle: negligible velocity, and it exits (a) is isentropic (b) has an efficiency of 94 percent

The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false