Question

求大神帮忙翻译一下这道题

http://wenku.baidu.com/view/2fca8a6a561252d380eb6e26.html
谢谢了

Answer 1

第三十九国际物理奥林匹克竞赛-河内-越南- 2008
Theoretical Problem No. 1
理论问题1号
WATER-POWERED RICE-POUNDING MORTAR
water-powered rice-pounding砂浆
A. Introduction
A.介绍
Rice is the main staple food of most people in Vietnam. To make white rice from
大米是许多越南人民的主食。使白大米
paddy rice, one needs separate of the husk (a process called "hulling") and separate the
水稻稻壳，需要单独的（这一过程称为“脱壳”）和分离
bran layer ("milling"). The hilly parts of northern Vietnam are abundant with water
糠层（“铣削”）。越南北部丘陵地区丰富的水
streams, and people living there use
溪流，居住在那里的人使用
water-powered rice-pounding mortar
水动力的水稻捣砂浆
for bran layer
麸层
separation. Figure 1 shows one of such mortars., Figure 2 shows how it works.
分离。图1显示了一个这样的迫击炮。，图2显示了它是如何工作的。
B. Design and operation
B.设计和操作
1. Design
1。设计
.
。
The rice-pounding mortar shown in Figure 1 has the following parts:
水稻在迫击炮图1中的下列零件：
The
的
mortar
砂浆
, basically a wooden container for rice.
水稻，基本上一个木制容器。
The lever
杠杆
, which is a tree trunk with one larger end and one smaller end. It can rotate
这是一个与一个更大，树干和一个较小的一端端。它可以旋转
around a horizontal axis. A
绕水平轴。一个
pestle
杵
is attached perpendicularly to the lever at the smaller
在较小的垂直地连接到杠杆
end. The length of the pestle is such that it touches the rice in the mortar when the lever
终点。的杵的长度使它涉及水稻在砂浆当杠杆
lies horizontally. The larger end of the lever is carved hollow to form a bucket. The shape
水平地躺。杠杆的较大的一端的雕花镂空形成一桶。形状
of the bucket is crucial for the mortar's operation.
用的桶灰浆的运作是至关重要的。
2. Modes of operation
2。操作模式
The mortar has two modes.
砂浆有两种模式。
Working mode
工作模式
. In this mode, the mortar goes through an operation cycle illustrated in
。在这种模式下，砂浆通过运行周期的说明
Figure 2.
图2。
The rice-pounding function comes from the work that is transferred from the pestle to
水稻的冲击作用来自于工作，从杵
the rice during stage f) of Figure 2. If, for some reason, the pestle never touches the rice,
在第一阶段F米）图2。如果，由于某些原因，杵碰不到饭，
we say that the mortar is not working.
我们说，砂浆不工作。
Rest mode with the lever lifted up
与杠杆举起休息模式
.
。
During stage c) of the operation cycle (Figure 2),
在C阶段）的运行周期（图2），
as the tilt angle
由于倾斜角
α

increases, the amount of water in the bucket decreases. At one
增加，桶中的水的量减少。在一个
particular moment in time, the amount of water is just enough to counterbalance the
在特定的时刻，大量的水就足以抵消
weight of the lever. Denote the tilting angle at this instant by
杠杆的重量。表示在这一瞬间的倾斜角
β

. If the lever is kept at
。如果杠杆保持在
angle
角
β

and the initial angular velocity is zero, then the lever will remain at this
和初始角速度为零，然后将保持在这一水平
position forever. This is the rest mode with the lever lifted up. The stability of this
位置永远。这是与杠杆举起休息模式。这种稳定性
position depends on the flow rate of water into the bucket,
位置取决于进入桶水流量，
Φ

. If
。如果
exceeds some
超过部分
value
价值
Φ

2
2
Φ

,
，
then this rest mode is stable, and the mortar cannot be in the working mode.
在此休息模式是稳定的，和砂浆不能在工作模式。
In other words,
在其他的话，
is the minimal flow rate for the mortar not to work.
对砂浆不工作的最小流量。
2
2

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十分感谢，不过你好像没有翻译完，原文可以不写，翻译完还加分