c****h
发帖数: 590 | 1 顶技术帖!
跟拍面大小，string pattern, 也有关系吧。
maneuverability. Also known as Moment of Inertia or Second Moment,
swingweight is dependent on several factors, including racquet weight,
length, balance, head size. |
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g*****y
发帖数: 7271 | 2 I never bothered to find a clear definition for swing weight. But from its
name, it should not be the same as energy or 转动惯量. Instead, it is more
likely to be proportional to mass/weight. In that sense, I think venus's
estimation would make better sense, although he did not consider more
detailed
factors such as different weight distribution above and below balance point.
maneuverability. Also known as Moment of Inertia or Second Moment,
swingweight
is dependent on several factors, including ra... 阅读全帖 |
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a****n
发帖数: 4734 | 3 我转的英文资料你没看吧？
转动惯量 英文叫: moment of inertia 起这个英文名的人大概也是不知道what weight
means in English.
你大概对力学了解不多，这也没什么，谦虚点没坏处。
think |
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e***y
发帖数: 1443 | 4 刚才在craigslist看到这拍，中古的，这个算什么行情：
"RARE" - Dunlop - Max 200G - John McEnroe - Graphite Injection - Max Series
- Vibration Control - for optimum performance John McEnroe recommends a
string tension of 55lb - made in England - L4 L1½ Grip - Used - Very
Good Condition! - comes with cover - $200.00
好东西么？
还有几个：
Pro Kennex - Graphite Ace - mide size - Graphite/Wood - Graphite inlaid - L3
4 1/8 Grip - The frame combines selected american ash & maple with a
Graphite inlaid to provide the advantages o... 阅读全帖 |
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b*e
发帖数: 3845 | 5 这个可能个人感觉不同，我个人认为ww这个flick 是pace 兼rpm的主要来源，要hit
through 多些，就在flip的时候拍面多给些。转体兼backswing造势inertia当然也很重
要，但对球pace的作用远没flip作用大，forward swing过早加速反而会造成flip速度
慢。这个只是一些感觉，也许有违理论，不太容易说清楚。
the |
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P***s
发帖数: 11672 | 6 sigh,为什么就没人知道英文名字呢。根据我google的结果，从易到难分别是
easy series: beginners workout, toning workout, relaxation workout
hello fitness: Wake Up Body, Invigorating, Goodbye Inertia
Fun Challenge: Burn off, Firming, Upside Down
（如果错了，请更正） |
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C******s
发帖数: 270 | 7 来自主题: ClassicalMusic版 - 恰空 给你篇文看
On the Marionette Theatre
by Heinrich von Kleist
Translated by Idris Parry
One evening in the winter of 1801 I met an old friend in a public park. He
had recently been appointed principal dancer at the local theatre and was
enjoying immense popularity with the audiences. I told him I had been
surprised to see him more than once at the marionette theatre which had been
put up in the market-place to entertain the public with dramatic burlesques
interspersed with song and dance. He assured me... 阅读全帖 |
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b*s
发帖数: 82482 | 8 来自主题: LeisureTime版 - 就这样吧 详情如下：
Dear Tom and Ray: You lugheads -- and I mean that in a good way -- often
talk about the proper way to drive a manual transmission. Well, I have an
automatic and know nothing about shifting from "Drive" to "1" or "2" and
back. Those numbers aren't just for decoration, are they? Thanks for all the
laughs. -- Anne
Ray: Automatic transmissions are pretty much "set it and forget it" these
days, Anne; 99.9 percent of your forward driving can be done in "drive."
When the transmission needs to be ... 阅读全帖 |
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z*i
发帖数: 58873 | 9 其他国家也都禁了。 归其还是愿不愿意做的问题。
其实虽然我希望，但是我觉得彻底禁没戏。跟全世界都用公制美国就要用英制一样，这
是个传统，有巨大的inertia. 想改变传统要看得见的benefit远远超过cost才行，
marginal的cost-benefit很难说服人的思维惯性。
只要能不断增加拥枪的门槛就行了。。。。
mall |
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b*******t
发帖数: 33714 | 10 小的时候不懂，就算喜欢有兴趣也不会知道怎么去学
长大了，学业重了，inertia大了，再开始就难得多 |
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y*b
发帖数: 3190 | 11 THIS MESSAGE GOES
OUT TO FEAR, DOUBT,
LOGIC AND REASON.
To excuses, distractions, procrastination, inertia, critics, cynics,
realists, pessimists, resistance, conventional wisdom.
To the peanut gallery, the so-called experts, the good enoughs,
the urges to pass the buck,
the easy way out, the snooze button, the panic button,
and to that little voice in the back of your head that says,
“It can’t be done.”
To all of it, we apologize.
Because we don’t see what you see.
AT CANON, WE SEE IMPOSSIBLE
h... 阅读全帖 |
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m**x
发帖数: 8454 | 12 don't be too picky. he just talked in english and it's just an inertia to
continue speaking in english. |
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r*****8
发帖数: 2560 | 13 不会倒。
陀螺转动的时候，有进动和晃动。
晃动就是你讲的倒不倒的问题。晃动的角度，与陀螺旋转的角动量正相关。
与玻璃有没有摩擦力没关系。只与角动量有关。
定性描述很容易，定量描述比较困难。
陀螺的定轴性使它在玻璃面上不倒。
定轴性：
当陀螺转子以极高速度旋转时，就产生了惯性，这惯性使得陀螺转子的旋转轴保持在空
间，指向一个固定的方向，同时反抗任何改变转子轴向的力量，这种物理现象称为陀螺
仪的定轴性或惯性。 其惯性随以下的物理量而改变：
1.转子质量愈大，惯性愈大
2.转子旋转半径愈大，惯性愈大
3.转子旋转速度愈大，惯性愈大。
逆动性：
在运转中的陀螺仪，如果外界施一作用或力矩在转子旋转轴上，则旋转轴并不沿施力方
向运动，而是顺着转子旋转向前90度垂直施力方向运动，此现象即是逆动性。
逆动性的大小也有三个影响的因素：
1.外界作用力愈大，其逆动性也愈大；
2.转子的质量惯性矩（moment of inertia）愈大，逆动性愈小；
3.转子的角速度愈大，逆动性愈小。
而逆动方向可根据逆动性原理取决于施力方向及转子旋转方向。
http://zh.wikipedia.org/zh-cn/%... 阅读全帖 |
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t******n
发帖数: 2939 | 14 ☆─────────────────────────────────────☆
l63 (l63) 于 (Fri Jun 28 22:23:48 2013, 美东) 提到:
就是说只考虑重力和平面支撑力的作用, 不考虑其他力.
如果没有摩擦力, 这陀螺的下场会怎样?
☆─────────────────────────────────────☆
yeemartin (猪头) 于 (Fri Jun 28 22:33:55 2013, 美东) 提到:
不倒。
☆─────────────────────────────────────☆
l63 (l63) 于 (Fri Jun 28 23:06:18 2013, 美东) 提到:
那么进一步设想: 陀螺如果没速度的话, 肯定就倒了. 如果速度很高就能一直不倒.
那中间一定有一个临界点吧? 在那个速度上, 到底是倒还是不倒?
能不能大致讲讲式子怎么列? 怎么能算出来陀螺不倒?
☆─────────────────────────────────────☆
cxu (Salmon Fish) 于 (Fri... 阅读全帖 |
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z****6
发帖数: 10776 | 16 还是不知道怎么得到的结果
http://en.wikipedia.org/wiki/Gravity_of_Earth
In combination, the equatorial bulge and the effects of the Earth's inertia
mean that sea-level gravitational acceleration increases from about 9.780 m
·s−2 at the Equator to about 9.832 m·s−2 at the poles, so an
object will weigh about 0.5% more at the poles than at the Equator |
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h******e
发帖数: 9616 | 17 手贱了。。。
https://www.hg.org/article.asp?id=28265
Scientific Data
A normal passenger vehicle such as a car or small pickup truck will normally
take approximately 316 feet to come to a complete stop after recognizing
the need to stop. In comparison, a semi truck takes about 525 feet before it
comes to a complete stop after recognizing the need to stop. This is an
important aspect of a truck accident case as the stopping distance is often
a question answered through accident reconstruction. To accura... 阅读全帖 |
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D*****r
发帖数: 6791 | 18 What is wrong with priests and popes is that instead of being apostles and
saints, they are nothing but empirics who say "I know" instead of "I am
learning," and pray for credulity and inertia as wise men pray for
scepticism and activity. |
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l*****a
发帖数: 38403 | 19 George Bernard Shaw
The fact that a believer is happier than a sceptic is no more to the point
than the fact that a drunken man is happier than a sober one. The happiness
of credulity is a cheap and dangerous quality.
In your Salvation shelter I saw poverty, misery, cold and hunger. You gave
them bread and treacle and dreams of heaven. I give from thirty shillings a
week to twelve thousand a year. They find their own dreams; but I look after
the drainage.
All the sweetness of religion is conveye... 阅读全帖 |
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k*******y
发帖数: 56 | 20 hard to say leh
maybe inertia? or I am just not being brave enough to change
my life, maybe I am not cold hearted enough to break his heart.
maybe just because I have not yet found a substitute.
I always hold that even we can't be lovers, we should be friends.
After all, once we cared for each other, being it love or not.
Why do we have to be enemies?
After all, once there were happy moments between us. What is the
point making each other hurt because of the past?
I don't want anyone to feel hur |
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s*********9
发帖数: 9860 | 21 鱼对水说你看不到我的眼泪，因为我在水里．水说我能感觉到你的眼泪，因为你在我心
里。
“You couldn’t see my tears cause I am in the water.“ Fish said to water.
“But I could feel your tears cause you are in me.“ Answered water.
1快乐要有悲伤作陪，雨过应该就有天晴。如果雨后还是雨，如果忧伤之后还是忧伤．
请让我们从容面对这离别之后的离别。 微笑地去寻找一个不可能出现的你！
Happiness is accompanied by sorrow, and it would turn sunny after rain as
well. If rain remains after rain and sorrow remains after sorrow, please
take those farewells easy, and turn to smilingly look for yourself who is
never to appear.
死亡... 阅读全帖 |
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m**i
发帖数: 8296 | 22 听说~```貌似~```有种东西叫做~`inertia force~````````
//escapa~`` *^皿^*~~`` |
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w*****r
发帖数: 165 | 23 Thanks for the answer. I appreciate your input. Unfortunately, this is an
image, not an 实物. The shape was detected after edge detection and
interpolation. Somebody metioned an algorithm using covariance matrix and
eigenvalues of an inertia matrix. I don't know much about this, but it looks
like a good approach. I wonder if somebody here could provide a little more
information. Thanks.
7 |
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c**i
发帖数: 6973 | 24 Robin Harding and Clive Cookson, The latest developments in robotics
research; Is robotocs any nearer to fulfilling its promise? Financial Times
(FT), Nov. 28, 2009.
http://www.ft.com/cms/s/2/65030168-d7e4-11de-b578-00144feabdc0.html?nclick_check=1
("Our opponents’ KHR-1 robot kits, Sugiura explains afterwards, were beaten
by the carpet. Making a robot walk is hard: its upper body has greater mass
and inertia than the legs that support it, so when the robot stops, its
torso will try to keep goin |
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a***o
发帖数: 3734 | 25 that's true. However, google's monopoly can only be through
advanced tech, not market inertia.
lay person won't switch to Linux because install and maintain
is daunting to lay person. On the other hand, lay person won't
have problem switching to another software provider on web.
It is only another bookmark to a lay person. |
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发帖数: 1 | 26 胡扯，你做過自動駕駛麼？知道自動駕駛有多少sensor麼？SoC有幾個核心麼？知道每
個核心都要lockstep麼？你一個core一個thread，難道要自動車用64核處理器？
這個是現在的配置，未來會更多：
communication devices, thermal and stereo cameras, short-range radars, GPS/
Glonass receivers, rear-mounted Lidar scanner, forward-facing lasers,
inertia units, display units
就上面的這些東西，你不用OS給我fuse一下？你知道mars rover都有OS麼？ |
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发帖数: 1 | 27 胡扯，你做過自動駕駛麼？知道自動駕駛有多少sensor麼？SoC有幾個核心麼？知道每
個核心都要lockstep麼？你一個core一個thread，難道要自動車用64核處理器？
這個是現在的配置，未來會更多：
communication devices, thermal and stereo cameras, short-range radars, GPS/
Glonass receivers, rear-mounted Lidar scanner, forward-facing lasers,
inertia units, display units
就上面的這些東西，你不用OS給我fuse一下？你知道mars rover都有OS麼？ |
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s********1
发帖数: 581 | 28 转轴加速平动时torque=I*alpha还成立吗？例如当圆球沿着斜面滚下来的时候。如果力
矩，moment of inertia和角加速度都绕球心计算，torque=I*alpha还成立吗？此时，
球的转动动能还是(1/2)*I*omega^2吗？ |
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c*******r
发帖数: 54 | 29 Recent US government budgets have harmed the National Institutes of Health.
But the problems in the medical research system are deeper than just the
current budget. If you care about medical research, read this article in the
Proceedings of the National Academy of Sciences by Bruce Alberts, Marc
Kirschner, Shirley Tilghman, and Harold Varmus.
Alberts and his colleagues describe a hypercompetitive culture in science
that undermines the process of discovery.
Competition… has always been a part... 阅读全帖 |
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z******i
发帖数: 5114 | 30 I found this while I am reading ACI 209:
Although creep and shrinkage effects may be higher in
thin slabs than in beams (time-dependent deflections as
large as 5 to 7 times the initial deflections have been
noted,2g*3g the same approach for predicting timedependent
beam deflections may, in most cases, be used
with caution for flat plates and two-way slabs. These
include Eqs. (3-7), (3-8), and (3-10) for the effect of
compression steel, etc., and Eq. (4-3) for additional
long-time deflections. Th... 阅读全帖 |
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D*****I
发帖数: 987 | 31 一般的两种材料组合截面好象是根据杨氏模量的比值换算成另一种材料,相加.
但是圆形截面,我用SAP2000的SECTION DESIGNER比较,结果并不是这样的.
也就是说,我先让SAP2000算一个STEEL SHEEL(不填CONCRETE),然后算一个填满CONCRETE
的.
两者之差跟我按 E1/E2换算的合不上. SAP2000自己没有关于组合截面换算的解释.网
上也没有找到相关的文献.,是我孤陋寡闻吗?请高人指点. |
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a*******r
发帖数: 344 | 32 sap probably is right, check topics of confined concrete, mander model etc
CONCRETE |
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D*****I
发帖数: 987 | 33 搞明白了,我用了AASHTO 复合截面限定的"n",SAP大概用的是不同的值.
直接换算I的方法是对的.因为面积有分布的问题,会影响到I的计算. |
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K**********n
发帖数: 1197 | 35 学术界珍稀有限的原版外文资料，
Remote Mind Control Technology
Reprinted from SECRET AND SUPPRESSED: BANNED IDEAS AND HIDDEN
HISTORY, edited by Jim Keith, $12.95, available from
1-800-680-INET.
There had been an ongoing controversy over health effects of electromagnetic
fields (EMF) for years (e.g., extremely low frequency radiation and the
Navy's Project Seafarer; emissions of high power lines and video display
terminals; radar and other military and industrial sources of radio
frequencies and micr... 阅读全帖 |
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m*****t
发帖数: 3477 | 36 【 以下文字转载自 JobHunting 讨论区 】
发信人: bert (liuliu), 信区: JobHunting
标 题: Job opening for MEMS Characterization Engineer
发信站: BBS 未名空间站 (Wed Apr 2 17:50:52 2014, 美东)
Recently, the wearable devices such as iwatch is a very hot topic.
Inside the wearable device, one of the key device is MEMS Inertia sensor.
Currently there is an opening in my company working as MEMS Inertial sensor
characterization engineer. This is a good opportunity to enter into this
field. I am the hiring manager and if you are int... 阅读全帖 |
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m********g
发帖数: 15 | 37 With the picture of the irregular cross section, is there any particular
software for this problem? |
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l*****r
发帖数: 2122 | 39 最近在建一个human body的模型(kinetics/kinematics),需要重新研究下dynamics of
rigid body/multibody.
具体是通过安置在身上的markers的位置以及force plate提供的力学信息来求解各个关
节的受力及torque. 感觉比较头痛的是如何求各个segment每一时刻的moment inertia.
如果有人有经验,也麻烦指点我一下,非常感谢! (angular velocity and acceleration
is calculated by quaternion method)
(不好意思,好多词中文都不知道怎么说.@@) |
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a**********s
发帖数: 1075 | 40 We wrap a light, flexible cable around a thin-walled, hollow cylinder with
mass M and radius R. The cylinder is attached to the axle by spokes of a
negligible moment of inertia.The cylinder rotates with negligible friction
about a stationary horizontal axis. We tie the free end of the cable to a
block of mass m and release the object with no initial velocity at a
distance h above the floor. As the block falls, the cable unwinds without
stretching or slipping, turning the cylinder. The speed of h... 阅读全帖 |
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a**********s
发帖数: 1075 | 41 We wrap a light, flexible cable around a thin-walled, hollow cylinder with
mass M and radius R. The cylinder is attached to the axle by spokes of a
negligible moment of inertia.The cylinder rotates with negligible friction
about a stationary horizontal axis. We tie the free end of the cable to a
block of mass m and release the object with no initial velocity at a
distance h above the floor. As the block falls, the cable unwinds without
stretching or slipping, turning the cylinder. The speed of h... 阅读全帖 |
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s*****t
发帖数: 1994 | 42 inertia.
most ppl do not like changes. |
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s********1
发帖数: 581 | 43 转轴加速平动时torque=I*alpha还成立吗？例如当圆球沿着斜面滚下来的时候。如果力
矩，moment of inertia和角加速度都绕球心计算，torque=I*alpha还成立吗？此时，
球的转动动能还是(1/2)*I*omega^2吗？ |
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k*****a
发帖数: 1518 | 44 关于Newton's Laws especially Newton's 2nd Law of Motion是否适用于nanometer
scale. Let me first quote from "The Feymman Lectures on Physics" Vol. 1, page
2-6:
"The mechanical rules of "inertia" and "forces" are wrong -- Newton's laws are
wrong -- in the world of atoms".
So this quotation sets the tone of the applicability of Newton's Laws, i.e.
Newton's Laws can't be applied in the scale of "atoms".
Next, what's the scale of atoms.? Let me quote once again from the same book
and same page:
"An atom has |
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b***k
发帖数: 190 | 45 交流电机的Inertia and friction factor一般都在什么范围？和其功率成比例关系吗？
谢谢 |
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s*******l
发帖数: 11 | 46 我知道,对于一般直线Spring,计算它的有效M是它实际质量的1/3.
但对于旋转Spring, 我是否可以套用这个公式,认为它的有效J是它实际Inertia的1/3?
多谢各位大侠啦,急啊!!! |
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m********g
发帖数: 15 | 47 With the picture of the irregular cross section, is there any particular
software for this problem? |
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f*******r
发帖数: 204 | 48 如果只要数值解，Matlab就可以。读图，按点阵数值积分。很简单的程序就可以搞定 |
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