# Search results

1. ### Question about gases and kinetic theory

i have a question that I cannot solve; Show that the rms velocity of a sodium atom moving in a vaccum chamber at 300 kelvin is about 570 metres per second pV=nRT and 3pV=Nm<c^2>
2. ### Reduction Formulae

Define I(n) by I(n) = integral of x^n / square root(1+x^2) dx. Evaluate I(0), I(1) and then establish the reduction formula I(n) = ((root2)-(n-1)I(n-2))/(n) for suitable values of n, which should be stated Here is my attempt I found I(0) first,and got the answer to be...
3. ### Impossible Integral

1. integrate 1/(1+(xx-1)^0.5) I.E. Integrate 1 over the sqaure root of( x^2 - 1) 2. I started by rationalizing the fraction and then i split the equation into two. I THEN let x = root2 (tanh(u)) for the 1/(xx-2) fraction, and have no idea what to do from there :S
4. ### Lightning and Capacitance!

1. The base of a cloud has an area of 2*10^7 metres squared and is on average 1km above the ground. treating the base of the cloud, the ground and the intervening air gap as a parallel plate capacitor, calculate the capacitance.[relative permittivity of air = 1.0] 2. I tried to say C...
5. ### De Broglie wavelength, Maximum kinetic energy, and smoke particles

Ok, i have done question 1 now Any help with the other two would be colosally appreciated
6. ### De Broglie wavelength, Maximum kinetic energy, and smoke particles

I have a few questions: 1. 'small smoke particles in air are seen under a low magnification microscope to move randomly at a speed of 0.10mm/s. The speed of sound in air is 330m/s. Estimate the mass of the smoke particles. I cannot make the link between speed of particle and speed of sound -...
7. ### Wave Problem

I am stuck on a question about standing waves: 'The diagram below show's Melde's experiment and demonstartion of a stationary wave on a string' The string has 3 full wavelengths shown, and 3 points are marked: Point A is on an antinode, Point B is on the same antinode, but very...
8. ### Confused! X-ray spectrum

This is an example...
9. ### Confused! X-ray spectrum

Hello, I have studied X-ray emission when an electron beam is fired at a tungsten target - But when I was presented with the graph of Intensity versus wavelength, I was confused... I saw a curve, and on it there were spikes. What are these spikes, and why are they caused? Something to...
10. ### Hydrogen Spectrum - Help!

But if UV transition requires a greater energy change, then why is it nt frm -1.4 to -5.4 * 10^-19???? Thanks
11. ### Hydrogen Spectrum - Help!

Hi, I have a question concerning a hydrogen spectrum: There are 4 energy levels drawn: Starting from the top -1.4 * 10^-19 Joules -2.4 * 10^-19 Joules -5.4 * 10^-19 Joules -21.8 * 10^19 Joules 1st question: Going from the second level to the third from the top (from -2.4 to...

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13. ### Water mechanics homework

Yes, I have got the horizontal speed to be 3.5 metres per second The vertical speed is 11.5 metres per second But what trignometric function? I do not know of any which can predict the vertical entry angle of a perabola
14. ### Water mechanics homework

Oh! That seems right - thank you very much! One last question - how do you calculate 'the angle which the diver makes, to the vertical, upon entry to the water' ??? Thank You, again
15. ### Water mechanics homework

Ah! That makes much more sense! Thank You Finally, make I ask you - how could you calculate 'the angle which the diver makesm to the vertical, upon entry to the water?'
16. ### Water mechanics homework

Ok, but he has water beneath him for all 8 metres. The question does not say that he runs 6.5 metres and then falls, it says he travels 8 metres in the air... So i am not sure
17. ### Water mechanics homework

Wait - maybe I am misinterpreting the whole question - when is says ' how long over the water,' what does that mean? Thank You
18. ### Water mechanics homework

Thank you! That gives the correct answer. But I have one question - If it takes 2.3 seconds to travel 8 metres, and takes 1.87 seconds to travel 6.5 metres - then why is the answer not 1.87? Since the time above the rock is the time taken to travel 6.5 metres, right?
19. ### Water mechanics homework

I agree - but I do not appear to get the answer of 0.44 seconds. This is how I did it - If t = 2.3 seconds Speed = d/t =8/2.3 = 3.5 metres per second Assuming velocity remains the same (which it does), then to travel 6.5 metres will take : T = d/s = 6.5/3.5 = 1.87 seconds. What...
20. ### Water mechanics homework

Hi - It is my fault - I have phrased it poorly. The Diver takes off and travels forward 8 metres, by the time he has hit the water - however, 6.5 metres of the 8 is covered above the rock. The other 1.5 metres is covered as he is now falling down past the rock.
21. ### Water mechanics homework

A cliff diver takes off horizontally from a cliff face 26.5 metres above the surface of the water. In the course of his flight, he travels 8 metres forwards, of which all but the last 1.5 metres of horizontal motion is above rock. In other words, he travels 6.5 metres in the air horizontally...