In an article its written,
$$\Omega_{\nu} = \frac{\rho_{\nu}}{\rho_{crit}}=\frac{\sum m_{i,\nu}n_{i,\nu}}{\rho_{crit}} = \frac{\sum m_{\nu}}{93.14h^2eV}$$
Now I am trying to derive this for myself but I could not. Can someone help me ?
So the values are,
##\rho_{crit} = 1.053 75 \times...
1/2 m v2 + mgh = 1/2 k x2
1/2 (5) (9) + (5) (9.81) x = 1/2 (200) x2
100 x2 - 49.05 x - 22.5 = 0
x = 0.779 m or x = - 0.289 m
Answer key says the answer is 0.289 m but in my opinion the answer should be 0.799 m because I take h = 0 at the position where the spring has maximum compression so...
After seeing a discussion about graphs of the relationship ##x^x + y^y = r^r##, it got me interested in attempting to see what the graphical appearance of ##{^{\infty}x}+{^{\infty}y}={^{\infty}r}## would look like. The first step I did was use the relationship of...
Here's the problem:
Suppose that Carl wants to estimate the proportion of books that he likes, denoted by 𝜃. He modeled
𝜃 as a probability distribution given in the following table. In the year 2019, he likes 17 books out of a
total of 20 books that he read. Using this information, determine...
Basically looking to find out what the maximum amount of load you could put on the center of a structure like this would be, in theory.
Top Beam:
The top "Beam" of the assembly in the drawing is 3"x 3"x 3/8" square tubing, 112.5" long
Supporting Beams:
The beams supporting each end of the Top...
The Eddington luminosity gives a limit on the mass accretion rate of the black hole and therefore of the mass of the black hole.
L_edd = 13*10^38 M/M_sun [erg s-1]. When I calculate from this I get that the maximum mass is M = 10^(-8)M_sun... which is impossible. Any ideas?
So, I recognise that:
$$ma=pg\left( L^{2}\right) \left( L-y\right) -\dfrac {1}{2}pgL^{3} $$
whereby $$pg\left( L^{2}\right) \left( L-y\right)$$ is the upthrust while the other is mg.
So, to find the largest speed of cube, I will assume that acceleration is zero since the acceleration slowly...
Given: V_1 = 10 L, V_2 = 22 L
Not sure what I need to do here. We are told to ignore heat transfer, and the problem suggests that this is not a steady-state problem. The gage pressure is given, so I think that means we need to calculate for the absolute pressure, which would be 997 kPa. Cp and...
I am reading about beams under distributed loading and shear stresses and needed to use the equation τ = VQ/It, where Q is the first moment of area.
I understand that Q is zero about the neutral axis, and that this is, in fact, how the neutral axis is defined. The first moment of area above the...
Homework Statement: I have to design a rigid wheel for a 4 wheel vehicle that will be able to traverse rough terrain. The wheel I have in mind is a cylinder with two disks with spokes at almost both edges.
I don't know how thick the cylinder or how many spokes the disks should have so I...
Hi,
after calculations I end up in the circuit below¨ (Thevenin equivalent)
So now I have to say Rth=RL and I will find Rx ?The initial circuit is this:
Thanks
By working with the following definition of minimum of a quadratic form ##r(\textbf{x})##,
##\lambda_1=\underset{||\textbf{x}||=1}{\text{min}} \ r(\textbf{x})##
where ##\lambda_1## denotes the smallest eigenvalue of ##r##, how would one tackle the above problem?
It is clear that the diagonal...
The green ray is moved upwards for clarity, they are all on same x-axis with no y component.
Theres a phaseshift at both reflections of the green light because n1 and n3 are > n2.
This results in a complete wavelength phaseshift, aka no impact on the wave.
That means that only the extra travel...
Hi everyone, just a quick question..
I tried this problem using Newtons laws, not conservation of energy, and I got an answer exactly half of what the correct answer is, and I'm not sure why. Here is what I did:
Net force = zero once the spring is compressed, therefore
mg - kx = 0
mg = kx...
I'm not really sure what I need to find exactly. From what I'm seeing, I could give C1 the max potential difference of 125V because it has the lowest capacitance, and because V = Q/C, this means the capacitor with the highest potential difference across its plates will be the one with the lowest...
In cosmological models the relationship between proper distance to a galaxy at the emission and absorption times can be written as ##d_p(t_e)(1 + z) = d_p(t_e)##
In this case in most cosmological models we get a maximum value for the ##d_p(t_e)##. This maximum value can be also seen from the...
If we put an emf equal constant onto a superconductor loop(we consider the resister of emf equal zero), then what is the maximum of current in the loop?
Hello.
I'm very interested to find out more about the maximum masses of white dwarf stars and of neutron stars. Please note that while my level in this forum is Basic, I am familiar with the role that the Chandrasekhar limit has played in our understanding of white dwarves. I was therefore...
Hi, So I have a uni project and were required to design a jockey wheel and corresponding power screw. We're given a maximum load and have to do the relevant calculations, moment of torque, efficiency etc. My question is I don't understand how to take the given maximum load and find the relevant...
I am reading Landau's Vol 5 on Statistical Physics and have trouble grasping some concepts in Section 20.
If I understand this correctly, the body and the medium are in direct contact and can exchange work and heat while the object can only exchange work with the body.
So the minimum...
We can solve for the maximum 5 lux illumination distance with the above equation.
E = 10.76*(35,000/d^2)
d = 275 feet (approximately).
However, the 5 lux illumination distance is not 275 feet. The 35,000 cd value is not an axial intensity value. It is at a point that is slightly down and to...
Hey guys !
My mother language is not English by the way. Sorry for spelling and gramme. :)
I'm curious to see if you can help me with my problem.I have already tried for almost a week and did not get to a solution. I also know, that the Maximum likelihood estimation is part of statistics and...
So I am almost sure I know how to solve this, just curious about the maximum velocity. Anyway, if you could double check my calculations, here it is.
##T = \frac{t}{n} = \frac{10s}{15} = \frac{2}{3}s##
##\omega = \frac{2\pi}{T} = 2\pi \frac{3}{2} = 3\pi##
a). position at ##t = 0.8s##...
How do we describe a construction of a 2-colorable graph where the degree of every vertex is greater than or equal to (|V|-1)/2? Based on that, what can be said about the dependence of maximum vertex-degree on k-colorability of a graph?
My first thought is that in order for a vertex to connect...
1] Let X,Y,Z be independent, identically distributed random variables, each with density $f(x)=6x^5$ for $0\leq x\leq 1,$ and 0 elsewhere. How to find the distributon and density functions of the maximum of X,Y,Z.2]Let X and Y be independent random variables, each with density $e^{-x},x\geq...
Hello everybody!
I bought some fittings for a feed system I'm building, and I need to handle pressures between 150 and 200 psi. I noticed some of them have max working pressures of about 1000 or 3000 psi, but others have relatively lower ones (150 psi, see...
Hey all,
Here's a neat picture:
The green arrow points towards one of the submaxima that I am curious about. It's the submaximum of the curve labeled 1.
1. represents the interference pattern
3. represents the diffraction pattern
2. represents the irradiance pattern
I guess that those...
Imagine the following scenario. A pipe is strapped to a larger "host" pipe using a steel strap and a spacer block as shown in the image below. If anyone could have a look at my calculations to confirm they are correct that would be brilliant!
Variables
Assuming the following general values I...
This is the form of the function above:
I started by equating (1) to 1/2:
$$T(\varphi)=\frac{r^{2}+\tau^{2}-2\tau\cos\varphi}{1+\tau^{2}r^{2}-2\tau r\cos\varphi} = \frac{1}{2},$$
which can be rearranged to:
$$2r^{2}+2\tau^{2}-1-\tau^{2}r^{2}=2\tau\left[2-r\right]\cos\varphi$$
using...
I tried to find it the following way but to no avail:
Let maximum value of ##\sigma## be ##S##
Now unfortunately, we do not have a maximum value for ##\dfrac{1}{r^2}## because the field point can be as close as we want to the arbitrary surface charge. (The field at a point on the surface is...
Hi!
I found interesting post here:
https://electronics.stackexchange.com/questions/325762/how-efficient-are-leds
However, it only gives the final results and not the steps he made. I tried to learn the formulas on wikipedia on my own but I couldn't figure out what variables need to have what...
I was able to find the maximum value for this function by differentiating and equating it to zero and find the time t and substitute it back to the original expression to get the max amplitude.
tm = -0.001012 s
v(tm) = 56.6
Another method that was presented in my book was can you explain how...
Maximum Slip
s=4/35
Synchronous Speed
ns=50*60/p
ns=3000 rev min-1
Speed at Maximum Torque
Torque is maximum when R2=sX2
For maximum torque, X2=R2/s
I'm not sure after this.
Hi,
So I have this question to solve and I have no idea how to do it.
It states: ''How are the maximum displacements of each pendulum related for ω1 and ω2? Draw a sketch that describes the motion of the system in each case. ''
The 2 angular frequencies that I have found are ω1 =√(g/l) and...
If I am given the width of the slit (b), wavelength of the light (λ), and the distance of the slit from the screen (D), how can I find the width of the central maximum (d)? My book says d/2=Dλ/b, but with no explanation and I don't understand why. Where does this formula come from?
Thank you...
Hi,
My attempted solution is in the image:
I choose the edge on the left side, but the solution should be similar on both sides (just substitute C for A).
(I missed to multiply by "g" in F_2.)
Is this the correct way of thinking? I'm not sure about the distance "D".
The graph is relationship between longitudinal force and slip ratio under the conditions of 0 longitudinal acceleration and flat road(0 angle of inclination). Which line represent FWD or RWD? Does FWD or RWD have higher maximum slip ratio?
Homework Statement
Fire hose has diameter of 4.0 cm and flow rate of 10 L/s. There is pressure of 2.2 bar inside the hose. How high the water can go at best? Water density is 1.00E3 kg/m^3 and air pressure outside the hose is 1.0 bar.
Homework Equations
Flow rate
$$ Q = Av $$
Newtons...
Homework Statement
A thin (460 nm) film of kerosene (n=1,20) is spread out on water (n = 1,30).
Light hits the (horizontal) surface of the film coming (almost) perpendicularly from above.
A diver underwater, below the film.
a) Find out the visible wavelength reflected into air that has the...
Homework Statement
A block is suspended by an ideal spring of the force constant K. If the block is pulled down by applying a constant force F and if maximum displacement of the block from its initial position of rest is X then, find the value of X.
Homework Equations
mg + F = XK + K(mg/K)...
Homework Statement
A detector of radiation called a Geiger-Muller counter consists of a closed, hollow, conducting cylinder with a fine wire along its axis. Suppose that the internal diameter of the cylinder is 3.00 cm and that the wire along the axis has a diameter of 0.2 mm. If the dielectric...
Homework Statement
Finding the general formula for max angular velocity ( answers say 0.839*(g/b)) but I do not understand how
Homework Equations
0.839*(g/b)
The Attempt at a Solution
Homework Statement
A particle is projected inside a tunnel which is 2 m high and must not hit the side or ceiling of the tunnel. If the initial speed is U show that the maximum range of the particle inside the tunnel
You may assume that the maximum range is attained when the projectile just...