The rotating element in a mixing chamber is given a periodic axial movement z = z0 sin 2πnt where z0 = 95 mm, and the frequency n = 2.7 s-1, while it is rotating at the constant angular velocity ω = 9.4 rad/s. Determine the maximum magnitude of the acceleration of a point A on the rim of radius r = 112 mm.

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?