此题为判断题(对,错)。
第1题:
起重机竖直吊起质量为m的货物,上升的加速度是a,上升的高度是h,则起重机对货物所做的功是______.
A.m(g+a)h
B.mgh
C.m(g-a)h
D.m(a-g)h
第2题:
6、起重机竖直吊起质量为m的重物,上升的加速度是a,上升的高度是h,则起重机对货物所做的功是()。
A.mgh
B.mah
C.m(g+a)h
D.m(g-a)h
第3题:
51、3 起重机械是指采用吊钩等起重工具,在间歇、重复的工作方式下,吊起、降低、举起、运输货物的机械设备。Hoisting machinery refers to the mechanical equipment that lifts, lowers or lifts and transports goods by lifting hooks or other lifting appliances in the intermittent and repeated working mode.
第4题:
49、3 升降是指用起重机械吊起货物,通过垂直运动实现装卸。Lifting up and down refers to lifting goods with lifting machinery, loading and unloading are realized by vertical movement.
第5题:
除了运送原油,管道还可以用来运输哪些货物?