【多选题】如图所示,用力F推着一个质量为m的木块紧贴在竖直墙壁上,木块此时处于静止状态.已知力F与竖直方向成角,则墙对木块的摩擦力可能()
【单选题】According to paragraph 4, why do scholars believe that the spots on the horses may represent a hunting scene?
A.
Other cave paintings near this one include hunting scenes.
B.
The spots are made of rocks that were attached to the wall.
C.
The spots are painted outside the horses' forms as well as inside them.
D.
The primitive writing is interpreted as an accounting of a hunt.
【单选题】如图所示,在两个大小相等的力F 1 和F 2 的作用下,质量为m的木块可在两长板之间以v的速度匀速向下滑落,如果保持两力F 1 和F 2 的大小方向不变,能使木块m以3v的速度匀速向上滑动,那么木块向上的推力应是( )
【单选题】初产妇, 30 岁,妊娠 38 周,早晨 6 时下床时自觉阴道流出大量稀水样液体, 9 点入院。正确的护理措施是
【简答题】If we say Jonathan Edwards represents the upper levels of the American mind, ______represents the lower levels.
【单选题】A salary increase would be entirely for merit. Increased ______in a business would represent real progress.
【单选题】According to the passage, words are______.
C.
represented either by sounds or letters
【单选题】Wang Feng’s _________ our school at the English speech contest proved to be a success.
【单选题】如图所示,某同学用压力 F压一质量为m的木块,使其始终静止在竖直墙面上。下列说法正确的是( )
D.
木块始终静止的原因是推力与木块的重力是一对平衡力