Recent content by zenite

I am doing a research project on measurement of residual stresses for Ti-6Al-4V that has been burnished. I did the first scan to get my peaks, and selected the last peak (the highest 2 theta value) for the stress scan (sin^2 PSI method). The problem is that the value I got for 3 samples (that...

Sorry, I skipped some steps. Here is the full working, pls let me know if its wrong. mgh = 0.5mv2 + 0.5Iw2 For pure rolling, v = rw mgh = 0.5mv2 + 0.5(kmr2)(v/r)2 = 0.5mv2 + 0.5kmv2 The inertia formula is used as kmr2, if its a sphere, k=1. For the acceleration down a ramp for a...

Yes, I do account for both. Will it affect the theory in any way? The formula I used to calculate final velocity: mgh = 0.5mv2 + 0.5Kmv2 where k is a constant dependable on shape of object (inertia) so v = sqrt (2gh/(k+1)) Then I need to compare the theoretical velocity (the one...

Hi Guys, I am doing an experiment to prove 1) Conservation of Energy 2) Inertia resist acceleration The experiment is simple, rolling objects down a ramp. So I timed the time taken for each object to reach the finishing line from rest. To prove conservation of energy, I increased the...

1. Integrate z2/(z4-1) counterclockwise around x2 + 16y2=42. Cauchy's Integral Forumula3. Solution I found the points z=1,-1,i,-i where the function is not defined. Using partial fractions to split them up, and integral them separately. Only points z=1,-1 lies in the contour, so...

thanks a lot. I couldn't get the part where lni = i(PI)/2, tried googling but couldn't find anything. but I could understand your working, you make it look so simple. I used the formula, elny = y for my working, that's where the ln comes from. but yours is much more simplified.

z = ii = ei(lni) so n=lni and the real part is cos(lni). is this correct?

1. Find the real part of z=ii by using De Moivre's formula. Homework Equations z= r(cos\theta + i sin\theta) zn= rn(cos(n\theta) + i sin(n\theta)) I tried using n=i to solve and got the ans 1i, but somehow feel that its not that simple. And the resultant argument I got from this...

Oh thanks for clearing my doubts. I have another question on convection. If an air gap exists between 2 walls, say, wall A and wall B. the convective heat transfer coefficient of the air is h. Assuming no radiation and conduction in the air gap, what is the heat transfer rate between the 2...

Ok, so radiation takes place between the object and the walls only? Is there no radiation taking place between the air and the object or is it insignificant as compared to the other modes of heat transfer? And yes, I realized that the formula that I put up earlier on is incorrect, since...

Ok, I think I got it. Please correct me if I am wrong. Rate of energy radiation of an object (T is given by qo = A\sigma\epsilonT4 If the object is in a chamber with wall temperature of Tw and surrounding air of Ta, then the object receives heat radiation from both wall and air. qwall to...

Lets say a hot object is at 500K and placed in a chamber with wall temperature of 300K. The surrounding air in the chamber is 320K. So what is the mode of heat transfer for the hot objection? There is convection and radiation. so the heat transfer rate, q = q(conv) + q(rad), right...