Recent content by bitty

Homework Statement We have a bead sliding on a frictionless hoop oriented vertically. First the hoop rotates about its center with rotation axis perpendicular to its plane. Second, the hoop rotates about a vertical axis as well. In both of these cases, are the constraints holonomic or...

Homework Statement Solve BVP y''[x]-y[x]=Cos[2x] using eigenfunction expansion. We know y'[0]=y'[Pi]=0 Homework Equations Fourier it up The Attempt at a Solution Is the corresponding Sturm-Liouville problem: f''[x]+/lambda*f=0? All the examples we've done have been of form...

Homework Statement An observation X has density function: f(x,/theta)=6x/(t^3)*(t-x) where t is a parameter: 0<x<t. Given the single observation X, determine the maximum likelihood estimator for t. Homework Equations Included below The Attempt at a SolutionFor a sample size of n...

Homework Statement In New York in the last 3 years there were 55 driving accidents. Assume all days are alike. What is the approximate probability that "in the next 3 years there will be at least 2 days with more than one accident". Homework Equations Poisson approximation The...

Let's see: P(R=1)=1*1/3*1/2=1/6 P(R=2)=1*2/3*1/2+1*1/3*1/2=1/2 P(R=3)=1*2/3*1/2=1/3 which add to 1 as desired. Then, by Bayes' Rule: P(R=3|R>=2)= P(R=3)/(P(R=2)+P(R=3))=2/5 ---My first question is: did I use Bayes rule correctly? It seems, correctly, that P(R=1) is irrelevant given the...

Homework Statement You have 3 urns: Urn 1 has 3 red balls, Urn 2 has 2 red balls, 1 blue ball. Urn 3 has 2 red balls 2 blue balls. You pick a ball from each urn and place it into Urn 4. You draw 2 balls from Urn 4 and they are red. What is the conditional probability that the 3rd ball is also...

Thanks! But using the same logic, the field would not be the same everywhere outside the cylinders because we would have it be proportional to 1/r not r. Understood. One more question: when trying to find the magnetic force between the two conductors of infinite length 'l' with currents I1...

these two problems though are analogous: in both we have 2 cylinders superimposed to create a hollow region. in this case though, the cylinders are identical and overlap instead of one being concentric to the other. In this case, is my solution along the y-axis correct? I have no idea who to...

Re-solving for the magnetic field along the y-axis (at x=0) since the two cylinders carry current in opposite direction we add the contributions from each cylinder. Each cylinder contributes a cosine component equal to a/r, where r is again the distance from one cylinder's axis to the point o...

This thread says they're vectors though... https://www.physicsforums.com/showthread.php?t=161491

Homework Statement Two infinitely long identical conductors carry equal current densities J in opposite directions parallel to the z-axis. They each have radius b and overlap so their centers are distance 2a apart. In the overlap a distance a from the center we have 0 current density (a hollow...