题型:判断题 It was almost eight years Iater _____ the young man got his doctor's degree and became an engineer.A.sinceB.whenC.beforeD.that 查看答案
题型:判断题 如图所示,有一金属平底煤油桶,放在水平地面上,他的质量mo=5㎏,桶的横截面积S=0.2㎡,内装有深h=0.5m的煤油,煤油的密度ρ=800Kg/m3,取g=10N/㎏,求:(1)煤油的质量;(2)煤油对桶底的压力;(3)金属桶对地面的压强. 查看答案