A closed, 0.4-m-diameter cylindrical tank is completely lled with oil (SG 0.9)and rotates about its vertical longitudinal axis with an angular velocity of 40 rad/s. Determine the di erence in pressure just under the vessel cover between a point on the circumference and a point on the axis.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false