Current-carrying capacity of wire. a copper wire of 0.040 in. in diameter is insulated uniformly with plastic to an outer diameter of 0.12 in. and is exposed to surroundings at 100∘f. the heat-transfer coefficient from the outer surface of the plastic to the surroundings is 1.5 btu∕hr ⋅ ft2 ⋅ ∘f. what is the maximum steady current, in amperes, that this wire can carry without heating any part of the plastic above its operating limit of 200∘f? the thermal and electrical conductivities may be assumed constant at the values given here:

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

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.

Fluids at rest possess no flow energy. a)- true b)- false