图示为定轴轮系，其传动比大小满足http://edu-image.nosdn.127.net/93603D7ACFC7BC11ABD365A70E34C361.PNG?imageView&thumbnail=890x0&quality=100。http://edu-image.nosdn.127.net/FE6DBD5A6879276CDCB4F09D9D174C0A.PNG?imageView&thumbnail=890x0&quality=100

已知图示有压混联输水管路（按长管计）各管段的沿程阻力系数http://edu-image.nosdn.127.net/1443EEDD6C2FA09BB126BDB9642044BA.png?imageView&thumbnail=890x0&quality=100，管径http://edu-image.nosdn.127.net/974CD2163F1D3BFAAEDC8DA84872F1CA.png?imageView&thumbnail=890x0&quality=100，管长http://edu-image.nosdn.127.net/76A594A1299928A8955B35FC20252D31.png?imageView&thumbnail=890x0&quality=100，流量http://edu-image.nosdn.127.net/1D52DAEDDD85EC829BD9C6E6F96AE143.png?imageView&thumbnail=890x0&quality=100,,则http://edu-image.nosdn.127.net/DAC36D2F41C6C3F84F776BC849094BA1.png?imageView&thumbnail=890x0&quality=100中k=（ ）。http://edu-image.nosdn.127.net/06283F2B8E549ACD83D8DDBBD7E4BE7C.png?imageView&thumbnail=890x0&quality=100

中国大学MOOC: 图示拉杆承受轴向拉力F的作用。设斜截面m-m的面积为A，则s = F /A为（ ）。http://edu-image.nosdn.127.net/D377FB4EA8EC279E303A24EB3EE86E17.jpg?imageView&thumbnail=890x0&quality=100

中国大学MOOC: 图示结构AB杆轴力为（ ）。http://edu-image.nosdn.127.net/E249E8D46FEC4CCBAECC0C1831801C5C.JPG?imageView&thumbnail=890x0&quality=100

曲柄如图示，若圆截面AB的弯曲刚度和扭转刚度分别为http://edu-image.nosdn.127.net/_PhotoUploadUtils_e9750fd8-ead1-4e20-8a44-c1289f9adc0c.png和http://edu-image.nosdn.127.net/_PhotoUploadUtils_632a65c8-8678-4ea7-bfe0-b0b25ef10fbe.png，关于其应变能,下列结论中哪个是正确的？（ ）http://edu-image.nosdn.127.net/2E9C1F732D9C2145014299FC43B9515E.png?imageView&thumbnail=890x0&quality=100