Each of the two grinding wheels has a diameter of 5.6 in., a thickness of 0.75 in., and a specific weight of 477 lb/ft3. When switched on, the machine accelerates from rest to its operating speed of 3840 rev/min in 4.9 sec. When switched off, it comes to rest in 31 sec. Determine the magnitudes of the motor torque and the frictional moment, assuming that each is constant. Neglect the effects of the inertia of the rotating motor armature and assume that the grinding wheels are uniform disks.

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

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Ahot wire operates at a temperature of 200°c while the air temperature is 20°c. the hot wire element is a tungsten wire of 5 um diameter and 2 mm in length. plot using excel current, heat transfer and heat generated by the wire for air velocity varying from 1-10 m/s in steps of lm/s? matlab the sensor voltage output, resistance, or assume nu 0.989 re033pr13 take air properties at tr (200°c20°c)/2 = 110°c properties of tungsten: c 0.13 kj/kg.k 3 p 19250 kg/m k (thermal conductivity) = 174 w/m.k