Which of the following is the purpose of fail-safe circuits?
a. fail-safe circuits are designed to provide overload protection for system components
b. fail-safe circuits are designed to protect electric motors against voltage surge
c. fail-safe circuits are designed to maintain constant current in electric motor coils
d. a, b, and c
e. none of the above

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

What is the major difference between thermoplastics and thermosetting plastics from the polymerization structure point of view?

When subject to a steady load (within elastic range) over a long period of time, what is the major difference in material behavoir between steel and plastic?