Technician A states that plain bearings are constructed of one material or layers of many different materials. Technician B states that plain bearings made of one material are aluminum bearings. Which technician is correct?

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

The drive force for diffusion is 7 fick's first law can be used to solve the non-steady state diffusion. a)-true b)-false

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?