Homework Statement
what is the difference between a distributed load with arrows pointing up like the once i have attached and just the standard distributed load where the arrow is pointing down. Does it mean the force is acting up the beam instead of down?the value given is -30kN/m. does that...
I have a set of data points {xi,yi} where each yi is a Gamma distributed variable where both the shape k and scale \theta depend on i.
I then fit the data points with a power law model y=a(x)b.
I would like to know the probability distributions for the fit parameters a and b.
Is...
Hi,
Suppose X_1, X_2,\cdots be an independent and identically distributed sequence of exponentially distributed random variables with parameter 1.
Now Let N_n:=\#\{1\leq k\leq n:X_k\geq \log(n)\}
I was told that N_n\xrightarrow{\mathcal{D}}Y where Y\sim Poisson(1).
Could anyone give...
Homework Statement
Show that for identically distributed, but not necessarily independent random variables with positive pairwise correlation ρ, the variance of their average is ρσ^2 + (1-ρ)σ^2/B.
ρ - pairwise corellation
σ^2 - variance of each variable
B - number of samples...
According to M-Theory there are 11 dimensions including time. 10 of these dimensions are spatial, so objects can move and therefore have velocity? Correct? According to Einstein's General Relativity whenever an object is not in motion in the three spatial dimensions, velocity is conserved...
Hi All
I'd like to know how I could calculate the work done by a distributed force on a string.
Let's say the force at a point x at a time t is given by
F(x,t).
Now the instantaneous amplitude of the string is given by y(x,t), say
I think that the work done by the force in...
Homework Statement
check out:
so this is for a bridge project right and that picture is simply a basic design just enough to get the jist to answer my question.
what I am wondering is, if 20kg's was applied to the very centre of that loading plate - is it fair to say that each of the long...
Having a hard time with failure theories. Beam length 20 feet, 6"h x 4"w. sigma yield is 40 ksi. How to calculate the maximum distributed load the beam could carry using von Mises and Tresca failure theories. I have my shear and moment diagrams drawn and know they are right. I found that...
Homework Statement
The random variables X1 and X2 are independent and identically distributed with common density fX(x) = e-x for x>0. Determine the distribution function for the random variable Y given by Y = X1 + X2.
Homework Equations
Not sure. Question is from Ch4 of the book, and...
Hello everyone,
I have been tirelessly searching the net trying to find out how to calculate the distributed capacitance of a multi-layer bifilar coil.
Just wondering if anyone here can point me in the right direction?
Why is dark matter distributed in a web rather than falling into clumps ?
Under the action of gravity normal matter falls into galaxies, stars, planets etc.
How is it that DM doesn't do the same but instead is in web form ?
Charge Q is distributed uniformly over a thin rod...
Homework Statement
Charge Q is distributed uniformly over a thin rod of
lying along the x-axis between points (a,0) and (b,0)
as shown. Please answer each of the following
questions.
a) What is the linear charge density on the...
Homework Statement
I am writing a MATLAB code to predict plate displacement for multiple load conditions using the rayleigh-ritz method. I have gotten the first three loads but I am struggling with the last load case.
I need to represent a distributed load for a flat plate that is piecewise...
Dear Good people,
I needed a help,
what will be the distribution of sum of n F distributed random variables?
what will be the distribution of sum of n non-central F distributed random variables?
Great if u can suggest some references too!
Thanks in advance!
Question:
X is normally distributed and the mean of X is 12 and standard deviation is 4
Find
i)P(0<=X<=12)
Solution
P(X=12) = Z(12-12/4)
=0 Stuck here!
what to do next
Hello,
I am attempting a problem in an older statics textbook an image of which is attached.
No matter what I try, I get a solution of between 0.52 and 0.53 metres and was hoping someone could verify if the textbook answer of 0.48m is right or wrong.
Thanks Heaps,
Scott.
Question: What is the probability that a random variable X with domain all real numbers will take a value in the closed interval [a,b]?
It seems to me that in order to answer this question you have to know how the real numbers are distributed. Given the appropriate distribution function, you...
I am given that the lowest value on a graph is 0 and that it's SD is 20, but I need to find the mean? How would I do that? I would think to use the Z-test formula but I keep getting 0 which is wrong for sure since 0 is the lowest value of the graph
Thanks
1. Suppose that two electronic components in the guidance system for a missile operate independently and that each has a length of life governed by the exponential distribution with mean 1 (with measurements in hundreds of hours).
(a) Find the probability density function for the average length...
This is a question from the GRE General Test, which I am not able to understand its solution. Maybe someone can help ^^
Question: The variable X is normally distributed. If the values of Xat the 45th,15th and kth percentile are 550, 350 and 450 respectively.
(A) K
(B) 30
Answer...
Hi ,
I got this question in my midterm today but up till now I don't know how to solve it ,
The Question is as follow :
If X and Y are two exponential Rv with different lambda . and there's a new Rvs Z and U are defined such that :
Z= 0 : X<Y and 1 ...
I've been struggling with this problem for more than 4 days now:
Let A, B and C be exponential distributed random variables with parameters lambda_A, lambda_B and lambda_C, respectively.
Calculate E [ B | A < B < C ] in terms of the lambda's.
I always seem get an integral which is...
1 Calculate the expected value of variable x (or E(x)) (number of trials * probability of success)
2 Calculate the variance (expected value * probability of a failure)
Take everything to the right of the decimal in the variance off. Then the range of future values is E(x) plus/minus the variance.
Homework Statement
Variables X and Y are uniformly distributed on [-1,1]
Z = X^2 + Y^2 where X^2+Y^2 <= 1
Show that Z is uniformly distributed on [0,1]
The Attempt at a Solution
If we set X=Rcos(theta) and Y=Rsin(theta), the joint pdf is R/pi where 0<=R<=1 and 0<=theta<=2pi...
hello
if we have set of stochastic variables representing the random time it takes to do something: X,Y,Z,W and C where C is the sum of X Y Z W, thus the time it takes to do these things in sequence. If:
X: N(30,5)
Y: N(30,3)
Z: N(20,2)
W: N(40,7)
makes C adding these together right, mean plus...
Homework Statement
Let me begin by saying that this will be a long post and will involve a few homework questions. I'm not looking for answers for per-say. Instead, I am looking to deepen my vague understanding of the Rayleigh-Ritz Method and how one can use it to find the mode shapes and...
Hi,
I understand how to get the electric field between two spheres of uniform charge,
\vec{E} = \frac{\rho \vec{d}}{3 \epsilon_0}
which is simplified because at a point \vec{r}, the vectors from each charge center combine to give the distance, \vec{d}, between centers (since \rho's can...
forgive for my ignorance, but i have a practical problem that i don't know how to approach:
X\sim\mathcal{N}(\mu,\sigma^2)
where \mu\sim\mathcal{N}(\mu_{\mu},\sigma_{\mu}^2)
and \sigma\sim\mathcal{N}(\mu_{\sigma},\sigma_{\sigma}^2)
what is the resulting distribution of X, in terms of...
Homework Statement
A horizontal beam 8m long, resting on two supports 1.5m from each end (supports are 5m apart), carries a uniformly distributed load of 25kN/m between the supports, with concentrated loads of 20kN at the left end of the beam, 30kN at the right end, and 40kN in the centre...
Are galaxies fairly evenly distributed regardless of which direction we look out from? Also are the oldest stars and galaxies that we can view also relatively evenly distributed in all directions?
I am asking because assuming that we are not in the center of the universe, I would imagine...
Homework Statement
To find the reaction at A and B. (See image below)
Homework Equations
Moments and Area
The Attempt at a Solution
Area of load: (0.3)(6) = 1.8kN
Moments about A: -(6)(0.15) + RB(0.6) = 0 --> RB = 1.5kN
4. The error and question
I get the reaction force at...
I am a little fuzzy on the meaning of Independent Identically distributed random variables. I understand the independent part but still not 100% on the identically distributed part. I understand that identically distributed means they have the same pdf and cdf but does this mean that they have...
I once ran into a nobel-winning astronomer at a conference and suggested to him putting small internet-controlled telescopes for free (and fully supported) on a the roof of any household that wanted one. The telescopes would be controlled by "The Project" from a central server, and the "owner"...
Homework Statement
A pendulum of length L has a distributed mass density r. Let the gravity be g and the initial angle pi/2, measured with respect to vertical. Will the pendulum remain straight when released from this configuration?
Homework Equations
None.
The Attempt at a Solution...
The life of a light bulb manufactured by a company is found to be normally distributed. if the bulbs last 400 days with a standard deviation of 75 days, what is the probability that a randomly chosen light bulb lasts?
a) at least 450 days?
b) less than 150 days?
etc.
Throughout the...
Homework Statement
How many rice grains are needed for an electric charge of a certain strength (I don't remember the value now but is it really relevant?) to be equally distributed amongst them?
Homework Equations
I hope you can answer that :)
The Attempt at a Solution
I can...
Hello, I am having difficulty approaching this problem:
Assume that K, Z_1, Z_2, ... are independent.
Let K be geometrically distributed with parameter success = p, failure = q.
P(K = k) = q^(k-1) * p , k >= 1
Let Z_1, Z_2, ... be iid exponentially distributed random variables with...
1. A solid conducting sphere is given a positive charge Q. Why is the charge uniformly distributed on the surface of the sphere only?
Homework Equations
3. I know there are electron clous where electrons hang out, but what happen when the sphere is given a postive charge? I don't...
I am looking for a Hoeffding-type result that bounds the tail of a sum of independent, but not identically distributed random variables. Let X_1,..,X_n be independent exponential random variables with rates k_1,...,k_n. (Note: X_i's are unbounded unlike the case considered by Hoeffding)
Let S=...
Homework Statement
Suppose U follows a uniform distribution on the interval (0, 2pi). Find the density of sin(U)
Homework Equations
The Attempt at a Solution
Well if U ~ (0, 2pi), then sin(U) should follow a distribution on [-1, 1]. I know one way to do tackle such problems is to...
Homework Statement
Let (S, \Sigma, P) be a probability space. Let X and Y be two random variables on S that satisfy P \circ X^{-1} = P \circ Y^{-1} (i.e. they are identically distributed) and such that E(X), E(Y), var(X) and var(Y) exist and are finite. Prove that E(X) = E(Y) and var(X) =...
Homework Statement
A beams is 3.0m long, it rests on two wide supports. The support A is 0.5m wide. Support B is unknown. Point A is taken to be the end of the beam on your left.
Support A has a loading intensity of 75 N/m.
The load on the beam acts with a force of 300N, 2.0m from...
Homework Statement
A positive charge is placed in the center of a cube. Are the intersections of the field lines with a side of the box uniformly distributed across that side. Explain.
===
I have missed some lectures due to getting the swine flu (ugh) and the material is not exactly...
Let \left(a_n\right) be the sequence
\frac{1}{2},\, \frac{1}{3},\, \frac{2}{3},\, \frac{1}{4},\, \frac{2}{4},\, \frac{3}{4},\, \frac{1}{5},\, \frac{2}{5},\, \frac{3}{5},\, \frac{4}{5},\, \frac{1}{6},\, \frac{2}{6},\,\mbox{...}
Suppose that 0\leq a<b \leq 1. Let N(n;a,b) be the number of...
Hello,
I want to simulate a plane thin rectangular board attached to one spring below at each end. (So there are 2 springs in total.) The springs span the entire edges. The spring-board-attachment is a rotatable axis.
I can't find out how the force acts on the springs. I don't know whether...
Homework Statement
A standard light bulb is claimed to have a lifelength of 8000 hours with standard deviation of 800 hours.
A newly designed light bulb is claimed to have a life length of 9200 hours with a standard deviation of 600 hours
Homework Equations
If 36 standard and 36 newly...
Does anyone else here do distributed computing? I have my PCs running World Community Grid and work on the Clean Energy Project. Does anyone else participate?