Recent content by Twich

Area of the semi circle is (0.5)∏(x^2 + y^2) The circle equation should be x^2+y^2 = r^2 So the semi circle equation in Q1Q2 should be y = √(r^2-x^2 ) |x|=√(r^2-y^2 ) Distance from origin to COM is ∫y dm/ ∫dm dm = ρ 2|x|dy = 2 ρ|x|dy = 2ρ√(r^2-y^2 ) dy ;from y= 0 to r ∫dm = 2 ρ...

Sorry for using wrong words. It give the distance from origin to COM. if semi circle lie in Q1 and k is the distance from origin to COM then you could find COM at (kcos45°, ksin45°) if Y-axis is the axis of semretical then COM is (0,√2 /3) since k = √2 /3

Still have three question left!

∫2*Pi*r/4 dr = ∫Pi*r/2 dr= area of semi circle = Pi*r^2 /4 ∫Pi*r/2*ρ(r) dr = mass of semi circle ∫Pi*r/2*ρ(r)*r dr = moment of inertia of semicircle Distantce from origin to Centre of mass of semi circle = moment of inertia / mass of semi circle

c = 84 / (25ab-84b-84) ; a,b,c <>0 if a, b, c are real number there are many solutions and a , b , c must not be zero. if c is integer then 25ab-84b-84 should be the member of {1,-1, 2, -2, 3, -3, 4, -4, 6, -6, 7, -7, 14, -14, 21, -21, 42,-42,84,-84} so you have 20 case to test case 1 ...

About mass, because relativistic mass is concerned as enerygy or momentum, how to calculate the accerelation of the mass when force F on it. Only m0 is considered as its inertia, isn't it? and another question? A rocket speed v relative to the earth. 1. how much relativistic mass (energy)...

The theory describes that the faster the mass travels , the heavier it is. But since everythig is relatively measure its velocity. Then How we know which mass would be heavier ?

Evidence has surfaced that the speed of light is not c in deep space. Is it true? <<unacceptable link removed>>

It seem not resonable to me that the electron felt lazy and drop down emit EM radiation. It sound reasonably to me if it hit something and emit EM radiation. Where could I find any mathematical prove that the classical physics was not correct? Thanks.

Since atom always emit EM-radiation, So the electron must lose the energy when collision occurred with enough energy. Thinking about this I come to the conclusion that the atom also need right energy to repair itself. It could only repair itself with correct amount of energy.

I really don't know anything of Quantum Mechanics. I could not understand why the electron only be found in the volume that form by a standing wave form. The standing wave is the result that the electron behave in atom not the causes! Could you suggest an easy (to understand) book or URL ...

there must be a force that repel the electron that get close to proton so it could not stop and proton. It's may be time-space force ^^ (Sorry. If it doesn't help.)

yes, you are right. You can use the simple form of energy conservation 1/2 m vf2 - 1/2 m vi2 = m a Δx => v2 - vi2 = 2aΔx Thanks.

No, it's not wrong at all. you could use the equation and mean velocity. But if you need to use the standard equation. it will be Xf = Vi*t + 1/2 a*t^2 (1) Vf = Vi + a*t (2) a = (Vf - Vi) /t (3) Xf = Vi*t + 1/2 (Vf -Vi) * t Xf = 1/2 (Vf +Vi)*t (4) Xf = 1000...

I think the probability is 1/60.