An uncoated, solid cable of length l = 1 m and diam- eter d = 40 mm is exposed to convection conditions characterized by h = 55 w/m2⋅k and t[infinity] = 20°c. determine the maximum electric current that can be carried by the cable if it is pure copper, pure aluminum, or pure tin. calculate the corresponding minimum wire temperatures. the electrical resistivity is rhoe = 10 × 10−8 ω ⋅ m for copper and aluminum at their melting points, while the electrical resistivity of tin is rhoe = 20 × 10−8 ω ⋅ m at its melting point.

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.

Which of the following ziegler nichols tuning methods the response of the controller to a step input should exhibit an s-shaped curve? a)-open loop mode b)-closed loop mode c)-both modes (open & closed) d)-none of the modes (open & closed)

What is creep? what is stress relaxation?