hai lớp 7A và 7B đi lao động trồng cây. Biết rằng tỉ số giữa số cây trồng được cuarlopws 7A và 7B là 0,8 và lớp 7B trồng nhiều hơn lớp 7A là 20 cây. Tính số cây lớp đã trồng

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Asimple rankine cycle uses water as the working fluid. the water enters the turbine at 10 mpa and 480c while the condenser operates at 6 kpa. if the turbine has an isentropic efficiency of 80 percent while the pump has an isentropic efficiency of 70 percent determine the thermal efficiency

Afan that can provide air speeds up to 60 m/s is to be used in a low-speed wind tunnel with atmospheric air at 35 c. if one wishes to use the wind tunnel to study flat-plate boundary layer behavior up to reynolds numbes of re 10, what is the minimum plate length that should be used? at what distance from the leading edge would transition occur if the critical reynolds nurnber were rer,e = 5 × 105?