A low in a marine weather report is an air pressure system the pressure at the center of which is ______.A.the highest over the areaB.the lowest over the areaC.higher than 1013 HPAD.lower than 1013 HPA
A low in a marine weather report is an air pressure system the pressure at the center of which is ______.
A.the highest over the area
B.the lowest over the area
C.higher than 1013 HPA
D.lower than 1013 HPA
相关考题：
Forces other than damaging winds are also at work inside tornadoes (龙卷风) . Sometimes,as the wind passes a house, the walls and ceiling burst apart as if a bomb had gone off inside. This explosion is caused by the low air pressure at the center of a tornado.The pressure at the center of a tornado is usually 13 pounds per square inch. However,inside the house the air pressure is normal, about 15 pounds per square inch.The difference of 2 pounds per square inch between the inside and outside pressure may not seem like much. But suppose a tornado passes over a small building that measures 20 by 10 by feet. On each square inch of the building, there is 2 pounds of pressure from the insidethat is not balanced by air pressure outside the building. On the ceiling, that adds up to an unbalanced pressure of 57600 pounds. The pressure of the four walls adds up to 172800 pounds.If windows are open in the building, some of the inside air will rush out through them.This will balance the pressure inside and outside the building.But if the windows are shut tightly, the huge inside pressure may cause the building to burst.Unfortunately, heavy rain often occurs in the storms that later produce tornadoes,so people often shut their windows. This may cause far worse damage later.21、 What did the paragraph before this passage most probably discuss?A、 Measuring rainfall from a stormB、 The kinds of damage caused by explosionsC、 The powerful winds of tornadoes22、 Which of the following is the main topic of the passage?A、 How tornadoes can be preventedB、 When tornadoes usually occurC、 Why tornadoes cause so much damage23、 Tornadoes can destroy buildings because the()A、 force of a tornado increases the air pressure in a buildingB、 air pressure inside a tornado is less than the air pressure inside a buildingC、 air pressure at the center of a tornado is over 172000 pounds24、 What is the difference per square inch between the air pressure inside a building and the air pressure inside a tornado?A、 2 poundsB、 13 poundsC、 15 pounds25、 What would happen if the windows are shut tightly in the stormy weather?A、 Tornadoes may be formedB、 The house may be apartC、 There may not be any pressure inside the building
Of the following, which one is not a term of Marine Weather Bulletin?______.A.Complex lowB.DepressionC.High pressureD.Ambient pressure
The circulation around a low pressure center in the Northern Hemisphere is ______.A.counterclockwiseB.variableC.clockwiseD.Anticyclonic
Low compressor head pressure in a refrigeration system can be caused by ___.A.insufficient condenser cooling waterB.excessive condenser cooling waterC.air in the refrigeration systemD.excessive refrigerant in the system
A decrease in barometric pressure is associated with all of the following except ______.A.rising warm airB.proximity to a low pressure areaC.inward spiraling circulationD.clear dry weather
A single barometric pressure reading of 28.60 indicates ______.A.rapidly improving weatherB.deteriorating weatherC.a severe low pressure systemD.fair weather and calm
Which general weather conditions should you expect to find in a low pressure system ________．A.Fair weatherB.Precipitation and cloudinessC.Scattered clouds at high elevationsD.Gradual clearing and cooler temperatures
If a weather bulletin shows the center of a low pressure system to be 100 miles due east of you, what winds can you expect in the Southern Hemisphere? ______.A.South-southwesterlyB.North-northwesterlyC.South-southeasterlyD.North-northeasterly
If your weather bulletin shows the center of a low pressure area to be 100 miles due east of your position, what winds can you expect in the Northern Hemisphere?______.A.East to northeastB.East to southeastC.North to northwestD.South to southeast
单选题A marine diesel engine is started by（）Asupplying high pressure oil into a hydraulic motorBsupplying high temperature air into the cylinderCsupplying high pressure air into the cylinderDelectrical igniting
单选题In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）Abroken valve springsBtight drive beltsChigh line voltageDair in the system
单选题Compared to a low pressure system，generally the air in a high is（）.Awarmer，less dense，and less stableBcool，more dense，and drierCmuggy and cloudyDextremely moist with high relative humidity
单选题Cast irons weakness in tension and under shock loading limits its use to low pressure steam, air, oil and low speed water fittingsThe above sentence, most probably means （）.Acast iron has weaknessBcast iron can stand up shock loadingCcast iron fittings are only suitable in low pressure situationDeast iron fittings are not suitable in low pressure situation
单选题A decrease in barometric pressure is associated with all of the following except（）.Arising warm airBproximity to a low pressure areaCinward spiraling circulationDclear dry weather
单选题The loss of the diesel engine cylinder air charge through leaky valves, piston rings, worn or scored liners, would be indicated by which of the following sets of conditions?（）ALow compression pressure and high exhaust temperatureBLow firing pressure and high exhaust temperatureCLow compression pressure and low exhaust temperatureDLow firing pressure and low exhaust temperature
单选题A single barometric pressure reading of 28.60 indicates（）.Arapidly improving weatherBdeteriorating weatherCa severe low pressure systemDfair weather and calm
单选题Which general weather conditions should you expect to find in a low pressure system（）.AFair weatherBPrecipitation and cloudinessCScattered clouds at high elevationsDGradual clearing and cooler temperatures
单选题The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）Asystem is overcharged with refrigerantBsystem is low on refrigerantCdischarge valves are leaking excessivelyDdischarge valves are leaking slightly
单选题If your weather bulletin shows the center of a low pressure area to be 100 miles due east of your position，what winds can you expect in the Northern Hemisphere?（）.AEast to northeastBEast to southeastCNorth to northwestDSouth to southeast
单选题Low pressure air is usually taken through （） or pressure regulators to a low pressure reservoir supplying a ring main through driers.Aglobe valvesBbutterfly valvesCgate valvesDreducing valves
单选题The greater the pressure difference between a high and a low pressure center，the（）.Adryer the air mass will beBcooler the temperature will beCgreater the force of the wind will beDwarmer the temperature will be
单选题The purpose of the refrigeration system low pressure cutout switch is to （）Aprotect the compressor from liquid flood backBprotect the compressor from low discharge pressureCstart and stop the compressor upon system demandDstart the compressor after a drop in the evaporator pressure
单选题An un-loader is installed on an air compressor to （）.Abypass the high pressure stage to the low pressure stage on 100% of the air compressors in serviceBprevent excessive inter-stage pressure buildupCcontrol compressor discharge pressureDremove all but the frictional load during starting
单选题Pump up the starting air reservoirs to their maximum pressure and （）the air reservoirs and air system.AopenBcloseCdrainDvent
单选题An indication of a diesel engine air intake being partially clogged, is （）.Alow firing pressure and low exhaust temperaturesBlow firing pressure and normal exhaust temperaturesChigh firing pressure and low exhaust temperaturesDhigh firing pressure and high exhaust temperatures
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.Aleaky discharge valves on the LP cylinderBleaky discharge valves on the HP cylinderCinsufficient intercooler coolingDlow ambient air pressure
单选题The circulation around a low pressure center in the Northern Hemisphere is（）.AcounterclockwiseBvariableCclockwiseDanticyclonic