studiot

That was why I added the bit about the selection in the second year being partly from those who has been selected before and those who had not been selected. The total of these must add up to 32% of the total population. However they have the same probability of selection the second year, whether they have been selected before or not.

Welcome Andohr. Since no one else seems to want to help, although there were plenty logged in who could have. You need to recast your thread title to correct algebraic expressions. The question is impossible as you have written it. (you need a way to make the coefficient of y2 negative) Then multiply out the two expressions (x+y+k)(x+y+j) (there i've done a bit for you already) and 'compare coefficients' That is form a set of simultaneous equations comparing the terms in your other expression with the result of your multiplication, amd solve them/ For instance jk = c is one. By the way none of your expressions are actually equations since they do not contain an equals sign- just a small point.

Can you explain that in the light of Newton's Law of Gravitation?

Summer was still very much with us in September, and your link refrers to a firebug sighting in Devon, which is only a few miles away. However your link did lead me to this alternative, which seems more likely since it refers to outer hair, which I think I can see from my photograph, although I could not now be certain to tell from memory http://www.britishbugs.org.uk/heteroptera/Rhopalidae/corizus_hyoscyami.html Many thanks, perhaps the search is near its end. +1 It may even be that these have another common name elsewhere.

Somerset, England.

That is really good. +1 The link contains an answer to your first question, not your second one.

Did you not bother to read the link? You need to complete your SF course in torque and moment before this second question can be answered

update see post#4 here http://www.scienceforums.net/topic/86036-earths-rotation/ Thank you swansont

I posted some information about a similar question in post#9 here http://www.scienceforums.net/topic/86022-lunar-energy/ and I thank swansont for the extra data I asked for there.

This was all rather diverting, there is much more to be said about moments in general and torque in particular, and why we should make a distinction if anyone is still interested.

I can't yet answer this, until Chikis has had a chance to have a go, as this is homework help. But think about the one piece (or pair of pieces) of information in the problem statement, not yet used. As a matter of interest I make W = 36/8 this way.

Well yes that is true, but that is what we are told.

You asked in your previous question if you can reduce the number of equations. This problem is the ideal situation for this, you do not need L = 2W, You can simply use 2W, whereever you have written L. So original area= A = W (2W) = 2W2 Can you now write the second equation so that (A - 30) = ??

Consider the selection of one single juror. Because there are two probability dependent 'trials or experiments' (the correct statistical words for selection) to consider. One for each year. The combined effect of probability in both trials has to be taken into account. Here is a sequence using Venn diagrams to show why the probability is the product of the individual probabilities. Start with the first year and select 32%. (Fig1) Say the population is 100 so 32 citizens are selected. The only jurors who can be selected both years will come from this 32%. (Fig2) So in the second year select 32% of these 32 (Fig3) ie 10 citizens. Now 32% of something is an old fashioned way of saying multiply by 0.32. So 32% of (32%) = (0.32 x 0.32) = 0.1024. Note that the 68 citizens who were not selected in the first year also have a 32% probability of being selected in the second year So by the same reasoning 0.32 x 68 = 22 citizens were not selected in the first year but selected in the second. Note that 10 + 22 = 32. That is the probability of being slected in the second year is 32% as expected.

Millivolts sounds right. Think of a solar panel or Hall effect generator.or even a humble accumulator. They achieve higher voltages by series connection od multiple unts.

Perhaps swansont has some more up to date data?

V is in metres per second L is in metres E is in volts B is in Tesla or webers per square metre Then everything is in rationalised MKS units (ISO metric). Note also that your formula uses the vector cross product VxB, since both B and V are vectors. This would normally also have a cosine of the angle between them, but since this is 90 cos(90) = 1.

See my reply in this thread http://www.scienceforums.net/topic/86021-lunar-azimuth/

No azimuth is a property of both the moon's position and the position of the observer. It is not a property of either the observer or the object alone but a combiantion of the two. It is the angle between the position of something and true North, or if you had aligned your theodolite telescope to true North it is the angle you would have to swing through to point at the object. I note you have another thread about Field Astronomy terms but I will try to answer them here. There are two axis passing through the earthly and celestial spheres. One is the axis ot rotation and it passes from North pole to South Pole, through the centre of the Earth and Celestial sphere, which have the same centre and NS axis. The other is a plumb line from the observer on the Earth's surface to the centre of the earth. If this line is extended to the celestial sphere it meets that sphere in the Zenith and Nadir So the zenith and nadir are properties of the observer alone, they are not properties of the observed object. A plane throught he centre of the earth at right angles to this axis is the horizontal plae for the observer. A theodolite measures the angle from this horizontal plane to the object in the sky ie on the celestial sphre as the altitude. The terms you were seeking for the elliptical path taken by objects on the celestial sphere are upper and lower transit or culmination for the highest and lowest altitudes. The left and right ends of the ellipse are called elongation. We can find some pictures if you wish.

It is curious that one way to construct a number system starts with nothing and generates a set with repeated copies as members to generate the natural numbers in the process. Another interesting observation on the empty set is that 'nothing' distinguishes the two basic objects in geometrical topology (of 3D), the sphere and the torus. The 'hole' is made of 'nothing', but unless it exists the object is a sphere, not a torus So mathematics is founded at least in part, on nothing at all!

Yes of course the Earth's rotation is slowing, measurably but slowly and the interaction betwen the orbiting moom and the Earth is in a large part responsible. But the fact remains that the water belongs to the Earth and rotates with it. Extracting tidal energy will not change this. I do not have verifiable information about the history of water bodies on the Earth or the Moon on a geological timescale so cannot comment on your other idea.

I can't see that it would make any difference to the rotation of the Earth since the energy of the tides has already been transferred to the water on Earth so diverting that energy somewhere else would not loose it to the planet. The fundamental rotation of the planet does not stem from the Earth - Moon interaction. BTW I hope you realise that the term tidal current refers to the horizontal movement of the water and the term tide refers to the vertical? Both motions can be utilised as an energy source, but only some of the energy of motion cna be extracted since the water must still move to extract the energy.

Did you never make mistakes in your college course? Well learn from them. So what would you do differently next time? And why only pharmaceutical companies? There is a vast range of anlaytical posts needed out there from water quality to wine or beer or cheese or youghurt.or cement production. this list goes on and on. So buck yourself up, smile and apply somewhere else, you have a (potential) skill that is in demand in most if not all industries.

Look at section 3.2.1 (Mechanics) of the current (2014 and beyond) A level syllabus for Physics in the UK http://filestore.aqa.org.uk/subjects/specifications/alevel/AQA-2450-W-SP-14.PDF It would seem the UK education authorities disagree with you. and here is the Further Mathematics syllabus (applied mathematics section) http://filestore.aqa.org.uk/subjects/specifications/alevel/AQA-6360-W-SP-14.PDF Once again torque is not discussed under rotational statics or dynamics. So UK educational specifications are in step with each other. Just as a matter of interest I have seen a number of modern textbooks draw a single curved arrow around an axis to denote turning moments of some sort. Ask yourself what would happen if this was actually applied in the fashion indicated to a real physical object? However I could not find any UK textbooks, serving the above syllabus, mentioning torque or offering such a description.

I am trying not to cross post with elfmotat, who I think is doing a grand job, but I would just like to reinforce one comment. You need to distinguish between potential and potential difference. This is a common confusion.