An SDOF undamped structure (i. e., c = 0) with lateral stiffness 150 k/in and a weight of 1200 kips is undergoing free vibration after being exposed to an initial velocity of 2 in/s and an initial displacement of 4 inches. For each 0.1 second time increment up to 1.2 seconds, find the acceleration, velocity and displacement of the structure. Plot the acceleration, velocity and displacement time history of the SDOF oscillator and label the maximum amplitude and fundamental period on each plot.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

The temperature of air decreases as it is compressed by an adiabatic compressor. a)- true b)- false

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?