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发表于 29-1-2010 11:52 AM
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请问一下matter的internal energy是什么来的？？ |
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发表于 29-1-2010 10:56 PM
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internal energy a molecule = kinetic energy of a molecule + potential energy of a
molecule |
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发表于 30-1-2010 05:37 PM
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回复 242# Log
er, can give me ur msn? Nid ur help |
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发表于 31-1-2010 01:35 AM
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发表于 3-3-2010 09:43 PM
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Can anyone tell me or teach me abt chap 1 form 6 de?
vick5821 发表于 23-1-2010 11:53 AM 
for chapter 1 to 4,i think most of them are already learn in form 4(if you are so excellent in physics in spm,no problem).however,starting from chapter 5(static) is a new thing to you...
be careful......
the most difficult part is electromagnetic induction(and all electric parts and magnetic part) and do not think the modern physics(the last few chapter)is easier than classical physics. when you learn,you will know that difficlut to explain...... |
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发表于 6-3-2010 10:31 PM
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can anyone help me?
1.explain factors influence the x-ray spectra for
a.filament current
b.applied voltage across x-ray tube
c.target material
2.explain the difference between x-ry emission spectra and optical atomic emission spectra
3.explain the production of continuous and characteristic x-ray spectra. |
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发表于 7-3-2010 11:32 AM
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can anyone help me?
1.expain the statement"reaction energy is the energy that is released in a nuclear reaction in the form of kinetic energy of the emitted,the kinetic energy of the daughter nucleus and the energy of the gamma-ray photon that may accompany the reaction".
2.why the fissile material musthas a critical size?what is meantby critical size?
3.why a nucleus is stable if the nuclear force greater than the coulomb force?
4.Φ=BA COSφ φ=ωt
and is maximum when cos φ=1
ε=NBAω sin ωt
and is maximum when sin ωt=1
why cos φ and sin ωt is maximum although the two ,one is sin one is cos.
5.state 3 similar characteristics of x-ray and γ-ray
6.expain the formation of moseley's law.
7.derive the bragg's equation. |
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发表于 19-3-2010 01:55 PM
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有没有人有2008和2009年的past year?要考试了，老师超爱出past year，这次她应该会出近几年的，但是我只有到2007年的哦～麻烦帮帮我好不好？谢谢～ |
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发表于 2-4-2010 10:32 PM
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本帖最后由 數學神童 于 2-4-2010 10:35 PM 编辑
if the earth can be assumed to be a perfect sphere of mass M and radius R, rotating about its axis with a constant angular speed W , what is the apparent acceleration due to gravity at its equator?Explain your answer. |
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发表于 10-4-2010 12:15 PM
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本帖最后由 meiling 于 10-4-2010 12:22 PM 编辑
can anyone help me?
7.derive the bragg's equation.
语曦 发表于 7-3-2010 11:32 AM 
先回答你一题。。
先画这个图。。
from constructive interference, path difference=m(landa)
tita=@
sin @=AB/d
d sin@=AB
from d diagram,
path difference=AB+BC= d sin@+d sin@=2d sin@
therefore, 2dsin @=m(landa)
其他的真的帮不到你，我以后的选科里面没有物理的，所以那些解释的我真的全部还给老师了。。
moseley's law这个syllabus里面没有的，你是那一课看到的？ |
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发表于 10-4-2010 09:09 PM
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回复 249# 數學神童
apparent acceleration of a mass at the equator , g' = g - Rω²
where g = acceleration due to gravity at the poles
explanation:
at the equator, the force acting on a mass m is given by F= GMm/R²
and the gravitational force consists of two components force that are the apparent weight and centripetal force
so, F= apparent weight + centripetal force
GMm/R²= mg' + mRω²
GM/R²= g' + Rω²
g= g' +Rω² , since GM/R² = g
thus, g' = g - Rω² |
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发表于 15-4-2010 08:50 PM
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post the stpm 2009physics paper 1answer here.
thank you very much. |
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发表于 17-4-2010 10:52 AM
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帮我这题下
A given turning fork,sounded with a string stretched between two points 135cm apart,produces 4 beats per second. The vibrating length of the string is altered to 136cm and 2 beats per second are produced. Find the frequency of the turning fork if the string vibrates in the fundamental mode in each case. |
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发表于 5-5-2010 03:32 PM
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想问看大家，谁能提供下physics formular list (english ) 英文版的。
谢谢！~ |
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发表于 7-5-2010 12:45 AM
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for chapter 1 to 4,i think most of them are already learn in form 4(if you are so excellent in phy ...
语曦 发表于 3-3-2010 09:43 PM 
那么说F4&5 的哪一课是比较重要的？那一课在F6时是一直在用？本身PHYSIC不是很好，所以想要温习回去。
谢谢 |
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发表于 7-5-2010 02:48 PM
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回复 253# 醉痴雪
frequency of turning fork =268 Hz |
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发表于 7-5-2010 02:53 PM
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回复 醉痴雪
frequency of turning fork =268 Hz
Log 发表于 7-5-2010 02:48 PM
How to get the answer? |
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发表于 7-5-2010 03:38 PM
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回复 257# 语曦
我是用beat frequency
F=frequency of turning fork V=sound speed
f= frequency of string
f-F=4 f-F=2
V/270-F=4 V/272- F=2
solve simultaneously to get F
如有错，请告诉 |
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发表于 7-5-2010 03:48 PM
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那么说F4&5 的哪一课是比较重要的？那一课在F6时是一直在用？本身PHYSIC不是很好，所以想要温习回去。 ...
jennykuwn 发表于 7-5-2010 12:45 AM
中六的物理比其中四中五的差太远了。。。把基础抓好先再说。。。 |
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发表于 7-5-2010 03:57 PM
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回复 语曦
我是用beat frequency
F=frequency of turning fork V=sound speed
f= frequency of str ...
Log 发表于 7-5-2010 03:38 PM
frequency is between 121-125HZ only..... |
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