Avolcanic plume puts ash into the atmosphere to altitude of 1m. the characteristic ash particle is a sphere with a diameter of 40 um and has a density of 1000 kg/m^3. consider a single ash particle in isolation that is travelling vertically at its terminal velocity (i. e. no acceleration). assume the density and kinematic viscosity of the air are independent of altitude and is given ,ρ=07kg/m3 and v= 1.5 x 10° m2/s. the drag coefficient is given by stokes' relation: cd =24/re. which of the following answers is closest to the length of time it takes for the particle to settle to the ground? a) 2 hours b) 53 hours c) 33 hours d) 21 hours

Line joining liquid phase with liquid and solid phase mixture is known as: a) liquidus b) solidus c) tie line d) none of the mentioned

When using the ohmmeter function of a digital multimeter, the leads are placed in what position relative to the component being tested? a. parallel b. control c. series d. line

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?