studiot

Maybe it doesn't like your spaces, MathJax won't parse your code for me. However [math]y = \int {f\left( x \right)} dx[/math] But you have to click on page refresh in your browser to get MathJax to activate. SF has stooped to the (low) level of other forums.

+1

I am guessing here because the OP is far from clear but I think the OP is referring to tightening down a block onto an unyielding sole or ground plate with his setscrews and a torque wrench. This will obviously cause an elastic shortening of the block, which he refers to as the 'deflection'. There is no reason for the block to bend, unless other unspecified forces are also acting. However, varatharajan, you have to give the dimensions of the block and specify its material to solve this question. Since practical measurement was mentioned, it is necessary to torque those screws up in stages or ther will be some warping forces involved.

Just so true. If Muskan does not know what an electrical current is, then he may well not know what a potential difference is either. A potential difference is often called a 'voltage', but you have to be careful to find out if something external is providing the voltage (eg a battery) or whether there is an internal voltage created. The first type of electrical current to study (there are others) is carried by moving electrons. So there must be a source of electrons that can move about. These can be generated by applying heat or light or enough externally applied voltage to a physical object. Left on their own a collection of mobile electrons will just drift about, trying to get away from each other since they all carry the same negative charge. (Remember like charges repel) Heat and light do not move the electrons in any particular direction, but applying a voltage does. This voltage drives the electrons away from the negative terminal and towards the positive one. The greater the voltage the bigger the effect. I also said that applied voltage can release mobile electrons. This is how we get sparks and the discharge in flourescent electric light fittings. So applying a voltage directs the current in a way that we want. Doing this is often likened to water in a hosepipe, but it is a very bad analogy because if you cut an electric cable, the current stops instantly at the cut. But water will trickle out of a cut hosepipe for a long time after cutting. If you understood this we can move on to other forms of electric current, in some of the different things Ed Earl mentioned (or perhaps he will tell you)

Looking over the past hour 7 trash threads started 1 real thread answer posted, but I have to scroll my screen to see it We had all hoped for heavier trash swatting with the new look, but it doesn't seem to have arrived yet.

This is consistent with this graph from Beerling. Note the age of the triassic 250 - 205 MYA, long before the end of the dinosaurs at about 60MYA

test mathType [math]\nabla = \Delta [/math] Codecogs \Delta =\triangle = \triangledown [math]\Delta =\triangle = \triangledown[/math] Sciweavers \Delta = \nabla = \triangle [math] \Delta = \nabla = \triangle [/math] Edit Looks just like the mishmash seen on other tech sites these days. and I have to press refresh page to get mathjax to kick in

The notification of another reply appearing whilst you are logged into a thread still works.

I see pagination and a sensible list of users online now showing. Thanks I have to observe that whoever wrote this version seems to have left CR and Dave to do all the real work and concentrated on unneccessary prettification. I feel for you both.

A very good point and what's more I hope that pagination has been retained. +1 My experience with super efficient sites is that if there is no pagination as you scroll down a thread the pages gets 'heavier and heavier' (ie slower) the further you go. So what about some of the SF threads that are 1000 posts long? Finally that blasted notification box has struck again. As soon as I logged on I got a notification that Ca'nRefsmmat has quoted me 1 hour ago. Surely you are not going to waste all that computing power telling every member every time someone quotes them? Think how many quotes are used here by members.

Fiveworlds +1 but I can't reference your post I'ts good to have a programmer or three with us. @The bosses, BTW I accidentally clciked twice on the green heart for 5worlds and a rather peremptory notice came up "you are not allowed to give reputation to this user" Could you not soften this message to something more human? Some of the other messages are more like from a Victorian germanic schoolmistress, rather than seeming to want to be friendly and helpful.

Thanks for the replies, from those who managed to find this post. Something else I noticed is missing. Post numbering. In a long thread it is very useful for all concerned to refer back to the post number. So I hope these will return when you have finished making changes Glad to see super/sub script back.

Both living and fossil stomatolites are available today.

But you are not on an airplane (are you?) Just testing another facility or three

You really can't be serious that this is an upgrade for a science site. Where is the list of recent posts? Where is my list of subscribed threads? Why does the users online list umpteen 'guests'. Where are the superscript and subscript? Tex test [math]\frac{{dy}}{{dx}} = \int {\sqrt {{x^3} - 15{x^2} + 3x - 8} } dx[/math] Why does a popup keep poping up to say 'Do you want to receive notifications from scienceforums ?' when I have already said no 15 times? That is enough for now Edit Well edit works, that I suppose is good Mathml seems also to work (quickly) unlike some forums which is good. Everything appears double spaced, whether I want it that way or not There seems to be no way to post the edit????????????????? Re- Edit You have to use the Edit Topic Button - quite illogical and confusing since I have already pressed edit to get there. Re-Edit 2 Now, of course once I leave it, I have no way to find this thread again to see if there are any replies. The text editor appears more friendly, however. What about reputation points, have these been abandoned?

Why are you converting lbs mass if you are talking about thrust? 6000 lbs of thrust (US units) convert to 26700N, the conversion factor is 1lb of thrust is 4.45 Newtons of thrust. https://simple.wikipedia.org/wiki/Thrust

Since the last thread was closed for a total lack of engagement with those offering scientific discourse, I rather hoped you would do the same here following the same action.

Thanks Strange, and +1 for finding the correct link, which says that the deflection distance was 0.16 inches, measured to .01 inches with vernier. This seems reasonable as it implies a scale marked on divisions of 0.1 inches divided a further 10 by the vernier. Now it is interesting what this means for the resolution of angle. At a radius of 3 feet or 36 inches 0.01 inches the angle subtended is given by [math]\frac{{\delta \left( \theta \right)}}{{360*60}} = \frac{{.01}}{{2\pi *36}}[/math] Which is approximately 1 minute of arc. (Don't you just love it when things cancel out so neatly) [math]\delta \left( \theta \right) = \frac{{.01*360*60}}{{2\pi *36}} = \frac{6}{{2\pi }} \approx 1[/math]

Yes it was inline with what I said. Lining the prisoners up like that is an interesting way of explaining which hat each can see, although it was not put that way in the original. You didn't answer the spinoff questions, why 3 black hats and why is the last person blind?

This is a good opportunity for you to understand the experimental method. I think by 'measurement uncertainty' you mean 'measurement resolution'. They are different. So the actual force was very small. Did Cavendish directly observe it? Of course not. He measured something else entirely. This something else was the twisting of a 6 foot beam, against a distance scale. So the effect of the small force was multiplied by a long lever arm. Now another of Newton's Laws asserts that, no matter how small the net force, it will accelerate a body and continue to do so for as long as the net force is obtained. So large effects can arise from small net forces if you wait long enough, which Cavendish did. Note the natural period of swing was about '20 minutes'. So back to the experimental method. Cavendish did not directly observe the force. G and the force were calculated from the data, but not by the formula you quote but by this one (modern version) [math]G = \frac{{\tau \theta {d^2}}}{{Mml}}[/math] Where tau is a previously determined constant of suspension Theta is the deflection angle d is the distance, that you mentioned, between the big and small lead balls M and m are the masses of the lead balls l is the length of the support rod. Now what you need to do, when discussing the experiment is to take that equation and develop the effect of measurement resolutions in each of those quantities, in accordance with the theory of errors. Further in experimental methods it is often known that certain effects change the observed readings and so must be allowed for. In Cavendish's case corrections were applied for:- 1) Each large Sphere also attracted the more distant of the small spheres 2) The attraction of the beam slightly icreases the deflecting couple. 3) The rods supporting the masses also cause attraction. A further experimental technique to increase precision is to take multiple readings and generate some kind of average. Cavendish took 29 readings for his average, but I am not sure of the statistical methods available to him for this calculation.

Just to take a very different tack from the current direction of the discussion, back to the thread title. Instinct v consciousness. Many argue in philosophy that our understanding (perhaps not the right word but I am equating this with consciousness) is entirely due to and conditioned by what we sense. Of course we also possess what is called the autonomic nervous system which conditions what we see and our reactions to it. The ground pushes against your feet, but are you conscious of that push? This contradicts the simplistic view that our knowledge that supports our consciousness is what we sense.

Yes it kinda depends upon the shape object, and, as Strange says, the material of the object may cause excessive damping. So a plasticine wine glass will not ring but a glass one can. You are not clear as to the shape, but taking your wine glass example here is an extract from a table of natural frequencies.

+1

maybe I didn't put it very well, but you have entirely missed the point. Creationists :- The Earth was created as being entirely suitable, yay perfect, for animals and Man. The truth: For 4 billion years the Earth was uninhabitable, yay deadly, to animals and Man.

Yes indeed, let's clear up what the wave function is. The momentum px of classical theory is replaced by the operator [math] - \frac{{ih}}{{2\pi }}\frac{{\partial \psi }}{{\partial x}}[/math] and the total energy E of classical theory is replaced by the operator [math] + \frac{{ih}}{{2\pi }}\frac{{\partial \psi }}{{\partial t}}[/math] in quantal theory. The wave function, therefore, is something that vibrates in time and space. The projection or shadow cast by it on the time axis is Energy The projection or shadow on the three axes of space are the three components of momenta.