1. A 500 ml cylindrical mug is filled level with the top of the mug with 90°C water. What is the water level relative to the top of the mug if the water is cooled to 20°C? The diameter of the mug is 10 cm. Ignore any surface tension effects.
2. A 4 cm diameter shaft is held in place by a bushing with an inside diameter of 4.1 cm. The bushing has a length of 1.5 cm and is lubricated with SAE 50 Oil at 80oC. If the shaft is rotated at a constant speed of 4500 rpm:
a. What torque must be applied to the shaft to overcome the fluid shear stress to maintain this rotational speed?
b. What power (in W) would be required to maintain this speed?
3. One way to study the surface tension effects in a liquid/solid system is to dip a pair of parallel plates into the container of the liquid. How far up in a pair of parallel glass plates, 0.3 mm apart, would water at 40oC be drawn up?
4. A 5 kg block is supported on a thin film of an unknown liquid 0.2 mm thick on an incline of 10o. Determine the viscosity of the liquid if the terminal velocity is 5.678 m/s. Assume the velocity distribution in the gap is linear, and the area of the block in contact with the oil is 0.25 m2. What is the possible identity of the liquid if the temperature is 20°C?