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如图所示，矿砂从传送带A落到另一传送带B的绝对速度为v1=4m/s，其方向与铅垂线成30°角。设传
送带B与水平面成15°角，其速度为v2=2m/s。求此时矿砂对于传送带B的相对速度;又问当传送带B的速度为多大时，矿砂的相对速度才能与它垂直？
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题目内容
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如果结果不匹配，请 联系老师 获取答案
更多“如图所示，矿砂从传送带A落到另一传送带B的绝对速度为v1=4…”相关的问题
机器传送带属于()纺织品(服装用、装饰用、产业用)。水龙带属于()纺织品(服装用、装饰用、产业用)。
A.2000±300
B.3000±300
C.4000±300
D.5000±300
A.人力拣选作业工艺方式
B.人+机动作业车拣选作业工艺方式
C.人+传送带拣选作业工艺方式
D.拣选机械拣选作业工艺方式
E.回转式货架拣选作业工艺方式
68.2 | 71.6 | 69.3 | 71.6 | 70.4 | 65.0 | 63.6 | 64.4 |
65.3 | 64.2 | 67.6 | 66.8 | 66.8 | 68.9 | 68.6 | 70.1 |
要求：(1)将这个时间数列中的测度值分为大于样本平均数的测度值和小于样本平均数的测度值，然后运用游程检验确定连续观察值是否表明该生产过程缺乏稳定性。
(2)将时间周期分为两个相等的部分，并运用t检验比较两个平均数。分析数据是否表明质量特征的平均水平发生了改变。(假定这两部分的数据都来自正态总体，并且方差相等)
Each day every person in the United States throws away more than five pounds of garbage(垃圾). There is more garbage now than ever before and most of it is made up of the packages and cans in which we put our food. The traditional way of getting rid of solid wastes is quickly becoming inadequate. Many cities are experimenting with newer ways of handling their growing piles of garbage.
One of these new ways is "recycling"(回收使用). Through recycling usable materials are taken out of garbage and made into something else. These usable parts of garbage are put through the cycle of going from a raw material to a finished product again.
In some cities a machine called Hydrapulper is being used to help recycle garbage. A Hydrapulper is like a huge mixing machine. The garbage is dropped onto a conveyor belt (传送带) that feeds the machine. At the same time, water is pumped into the Hydrapulper. With a mixing action, the Hydrapulper throws out the heavy metal objects that can later be sold as waste metal. The rest of the garbage—paper, food, plastic, rubber, glass, wood, leaves, and other items—falls apart. The waste is then mixed with water and carried to another piece of equipment where glass, sand and small pieces of metal are thrown out.
With the Hydrapulper, up to 95 percent of the original garbage is made again useful. The rest turns into furnace ash(炉灰).
Traditionally, garbage is thought to be ______.
A．a worthless burden to big cities
B．something that can be reused
C．a raw material for making new products
D．able to be recycled but difficult to handle
