Ratio Definition and 1000 Threads

Homework Statement If the ratio of the energy densities of matter and radiation was much higher than it is today (by several orders of magnitude), in a few sentences describe what effect this would have on the redshift (or scale factor) when the universe switched from being...

as temperature of a conductor increases why does the ratio of conductivity to resistivity increase ?

Homework Statement For e^+ e^- collisions at \sqrt{s}=5 GeV, estimate the ratio of the rates at which interactions produce hadrons and \mu^+ \mu^-Homework Equations \sqrt{s} = 2E = E_{cm} \Gamma = \frac{S |p|}{8 \pi \hbar m_1^2 c} |M|^2 where M is the matrix element \frac{d \sigma}{d...

Homework Statement we are looking at two stars in the eridani system, eri B and eri C. the period of the system is 247.9 years. the system's measured trigonometric parallax is 0.201 arcseconds and the tru angular extent to the semimajor axis of the reduced mass is 6.89". the ratio of...

Hi all. I need help on an issue I can't figure out. What is the difference between 15x15 and 17x17 fuel when it comes to moderation properties? Standard fuel with these lattices have dimensions 15x15: pitch: 14.3 mm, d_rod: 10.77 mm 17x17: pitch: 12.6 mm, d_rod: 9.5 mm These geometries...

Homework Statement The ratio sin theta =-12/13 Homework Equations The Attempt at a Solution which comes out to according to my calcuations -0.9230, i then use 2nd sin function on my calculator and come up with -67.3 degrees this answer is legitimate but another way of writing...

You can see it here starting at 2:30 https://www.youtube.com/watch?v=http://www.youtube.com/watch?v=kkGeOWYOFoA My question is, how do you determine the position of the points used to draw the triangles and circles.

Martin Rees in his book Just Six Numbers says that in the early universe there 1 billion antiquarks and a billion and one quarks. Is that really known? How is known what the ratio of antiquarks to quarks was?

The following is an approximation problem. Given a ratio: D =\frac{ \sum a_ib_i}{\sum b_ib_i} I wonder what steps to follow to give a reasonable approximation. This is an intuition D =\frac{ \sum a_i}{\sum b_i}. Clearly, given that all b_i terms are the same, the approximation is the...

hello a plane would need a thrust to weight ratio of 1 of fly straight up without losing speed but how can a plane in level flight maintain its altitude with <1 TWR since to maintain a level flight you need to have lift = weight so your engine needs to supply enough power to generate...

What does the ratio c/a mean in solid state physics? I have attached a table with a an example. Cheers

Homework Statement I need help once again with this question below: Thanks, aeromat The Attempt at a Solution This is what I have so far: GP = GQ + QP GQ = GP + PQ GR = GP + PR GP + GQ + GR = GQ + QP[-] + PQ[+] + GP + PR + GP GP + GQ + GR = GQ + 2GP + PR I am stuck...

Homework Statement Tea served in a canteen is made from a mixture of two different types of tea, type A and type B. Type A costs €12.15 per kg. Type B costs €12.90 per kg. The mixture costs €12.65 per kg. If the mixture contains 7kg of type A, how many kilograms of type B does it contain...

Homework Statement A tank was 3/4 full of oil. 100 litres of oil were then used. If it was then 2/3 full, how many litres does the tank hold when full Homework Equations The Attempt at a Solution umm, I am not even sure how to get started, i know that 3/4 = 75% and 2/3 = 66.6%...

Does Poisson's Ratio only apply to material still in the linear elastic range or is it still true for the material that has undergone plastic deformation?

Homework Statement A container is filled with a mixture of nitrogen and oxygen. What is the ratio of the rms speed of oxygen molecules to that of nitrogen molecules? (Molar mass of oxygen=32gmol-1; molar mass of nitrogen=28gmol-1). Homework Equations v2=(v12+v22+...+vN2)/N The...

Hi. I have been banging my head against this problem for a while and I just don't get it. Maybe (probably) it's something wrong with my logarithm-fu or limit-fu. I just registered to ask this because I couldn't find an answer anywhere, and I've been reading these forums for a while for other...

Homework Statement a) Consider Glashow's model with general hypercharge assignments Y_L, Y_R, for the left-handed and right-handed fields, respectively. By demanding the correct electromagnetic couplings of the electron and neutrino to the photon, determine the ratio Y_L/Y_R. [8 marks]...

Homework Statement If the cross-section of the barrel of a pump is 5 square centimeters, the stroke of the piston is 20 centimeters, and the volume of the receiver, in which the air is drawn from, is 1 liter, calculate the ratio of the pressure of the air in the receiver to the original...

I know the cut off ratio is of the specific volumes, but is that it? And what exactly do they tell you

Its not obvious to tell by handles, so what is the ratio of female to male users.

Homework Statement 3rd class lever 5m distance from load to effort and 1m distance from effort to pivot. Load = 1962 Effort required to lift load = 11772N MA = 0.16 or 1/6 ( so there really is no MA) Calculate the velocity ratio of the system ? Homework Equations I have...

I am trying to get an understanding of what a good signal to noise ratio in terms of decibels. My SNR is roughly 20 dB, and am concerned about being able to resolve the signal from this.

Hi I'm looking for a good description (high-school to 1st year level) why the ratio of protons to neutrons matters for stability. Single neutrons are unstable, but in a nucleus they are stable and the more nucleons you have the greater the strong force. So why can't you have stable isotopes...

A block of wood with a density that is 750 kg/m3 is floating in a tank of water. How much of the wood is above the surface of the water D=M/V I've been trying for hours to try to figure this one out. The only info I'm given the the density of a block of wood in the water at...

I am trying to model the RPM at which the turbo I plan to fit to my BMW will develop the desired pressure ratio. I have determined air flow into the engine at the desired pressure ratio and have determined the rpm at which peak power and torque should arrive. I have also determined the size of...

I have a basic question on how the power efficiency of wind turbine affected by the gear ratio. Suppose there is a generator connected with the rotor through a gear enhancer, a higher angular speed of generator is obtained. Since a higher voltage is produced, we may think that the power...

The problem I am struggling with is this . . The centre of the Earth-Moon system is 4.7x10^3 km from the centre of the earth. Calculate; i.the ratio of the mass of the Earth with the mass of the moon. ii.The acceleration of free fall on the Moon's surface. Constants Distance between...

Homework Statement The p-V diagram in the figure below shows two paths along which a sample of gas can be taken from state a to state b, where Vb = 4.0V1. Path 1 requires that energy equal to 3.0p1V1 be transferred to the gas as heat. Path 2 requires that energy equal to 8.5p1V1 be...

Conserving Energy The Attempt at a Solution I started out using the above formula, but I don't understand how to get the speeds when only the masses are given.

Homework Statement In many locations, such as Lake Washington in Seattle, floating bridges are preferable to conventional bridges. Such a bridge can be constructed out of concrete pontoons, which are essentially concrete boxes filled with air, Styrofoam, or another extremely low-density...

Hi, I'm trying to find the aspect ratio of my model rocket-plane that I have for a horizontal flight competition for my aerospace class. It's like a rocket, with fins at the bottom, but it has two little triangular wings in the middle to stabilize it. Would I have to use a mixture of the two...

Homework Statement A 5.39-g bullet is moving horizontally with a velocity of +354 m/s, where the sign + indicates that it is moving to the right (see part a of the drawing). The bullet is approaching two blocks resting on a horizontal frictionless surface. Air resistance is negligible. The...

Hi. I was wondering if anyone had ever done a relationship analysis of compression ratio in relationship to efficiency. I have heard that higher compression ratio can often relate to efficiency, but I was hoping to find some kind of graph correlation on it, however I haven't been able to find...

I would like to get opinions when calculating Source Impedance Ratio (SIR) on a Power System. Usually when calculating a three Phase fault it only takes into account positive sequence components, obtaining the source impedance ratio via the ratio of the source positive sequence component...

How do u show, without using calculus, that if something initially has 3 times the velocity of another object, how much farther it will travel than the other? the exact question is: A wooden block is cut into two pieces, one with three times the mass of the other. A depression is made in...

I working on a new airfoil design. Please tell me the airfoil having highest lift to drag ratio, I need it for comparison.

Hello, this is my first post so please be patient. I studied mathematics and have actuary qualifications. I was always obsess with the golden ratio. I was wondering if there was a relation between quantum physics and the golden ratio. A hunch told me so.

Homework Statement The question is: A rod of 50mm in diameter and 0.8m in length is subjected to an axial load of 150kn. If the rod entends by 1.4mm and there is a decrease in diameter of 0.01mm, determine: The value of poissons ratio? Homework Equations v=lateral strain/longitudinal...

Homework Statement A pitcher can throw a baseball at 44 m/s. what is the ratio of kinetic energy to the rest energy E=mc^2. (can you use k=1/2mv^2 ?) Homework Equations rest energy=mc^2 K=gamma*mc^2 - mc^2 k=1/2mv^2 The Attempt at a Solution I am just not sure how to go about...

Homework Statement here's how the question goes: the magnitudes of the charges on two identical small metal spheres are in the ratio 5:1. the coulomb interaction force between them is F1. if they are brought into contact and then separated to their respective original positions, the coulomb...

Homework Statement The summation of n/lnn from n=1 to infinity Homework Equations Ratio and Comparison test The Attempt at a Solution http://i55.tinypic.com/2jxuue.jpg Alright so the way labeled "right way" on the picture is the right way according to the book but isn't the...

How can you determine the ratio of the keto tautomer of a compound to its enol form? I know which functional groups are associated with which but I have no idea how you'd use an IR spectrum for quantitative analysis like this.

in air foil : what is aspect ratio: A= b/c

Homework Statement (p,a) , (q,b) and (r,c) are the coordinates of three points on the parabola y^2=3x. If the x-coordinate for these three points form a geometric progression whereas the corresponding y-coordinate form an arithmetic progression, find the common ratio of the geometric...

Homework Statement Two skaters stand face to face. Skater 1 has a mass of 55 kg, and skater 2 has a mass of 75 kg. They push off one another and move in opposite directions. What is the ratio of skater 1's speed to skater 2's speed? Homework Equations KE=0.5*m*v^2 The Attempt at...

Homework Statement Beta = b/sqrt(mk) Explain how Beta can be interpreted as a ratio of time scales. What do the time scales measure? b: damping coefficient of spring (dimension: M/T) m: mass attach to spring (dimension: M) k: spring constant (dimension: M/T^2) The Attempt at a...

Homework Statement The apparatus shown consists of four glass columns connected by horizontal sections. The height of 2 central columns B and C are 49 cm each. The height of the liquid in A and D is 52.8cm and 51 cm resp (measured from the baseline). The water columns are maintained at...

[Solved] Kinematics ratio problem Homework Statement A force F produces an acceleration a when applied to a certain body. If the mass of the body is doubled and the force increased five-fold, what will be the effect on the following? a. its acceleration b. the distance the body travels in...

Homework Statement Assume all sn =/= 0, and that the limit L = lim|(sn+1)/(sn)| exist. a) Show that if L<1 then lim sn = 0 b) Show that if L>1 then lim sn = + oo Homework Equations There is a hint that we should select 'a' s.t. L<a<1 and obtain N s.t. n>N => |sn+1 < a|sn|. Then show that...