1) Relative to electrons and electron states, what does each of the four quantum numbers specify? 2) Cite two important quantum mechanical concepts associated with the Bohr model of
the atom.
3) Cite two important additional refinements that resulted from the Wave-mechanical
atomic model.

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.

Most leaks in reciprocating air compressors can be detected and minimized by: (clo4) a)-detecting leakage areas using ultrasonic acoustic detector. b)-tightening joints and connections c)-replacing faulty equipment d)-all of the given options

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.