studiot

Think carefully about how you are doing this. It is pretty well impossible to keep you hand in the centre of the circle with a string. I expect your hand is actually describing its own circular motion, not rotating about a point. This imparts sideways motion as well as circular. Twirling in a vertical plane as you describe also make it more difficult. Have a go with a very heavy weight and a more nearly horizontal circle, or watch the hammer throw in athletics. Which way does it go?

That's a really good start to your membership. +1 and welcome. Just note new members have a total of 5 posts in their first 24 hours (because of less desirable new members)

Of course holes have physical existence. They can interact with physical objects modifying the physical properties of those object. For isntance a steel sheet is impervious to the passage of water. Knock a hole through it and Voila.

May I ask why you are so interested in publically (discussing) habits most people would consider private? Posting in the lounge suggests this is not a medical (and therefore scientific) interest.

How about a double for two smileys?

We are still seeing banned users online here. Yesterday and today's crop

Whilst there are doubtless those sensitive to isopropyl alcohol, I don't think it is as dangerous as Sensei thinks. It is the normal active substance in antisceptic wipes (around70% is common), otherwise known as rubbing alcohol. As such it is rubbed onto the skin and even into puncture wounds. It's most dangerous characteristic is probably that it is inflammable.

Interesting example of interaction I never thought of. +1 Some folks achieve this (illegally) by placing a Police traffic cone on their 'space'.

113, It would help to know if you are starting calculus at high school or restudying the subject more deeply at university? It may seem silly and obvious to say that when you start something you have to start somewhere. The way calculus was developed and the way we learn it is not the way it is formally collected together and written down in textbooks. So when you start (or restart study) there is much they don't tell you at first. This is not due to any malevolent intent, it is simply to make the presentation understandable. One of the reasons that differentiation is presented in the form it now appears is because there are many types of differentiation. You are studying the functions of a single real variable. The modern form can be extended to differention of Vectors (and tensors if you have heard of them) for instance. The idea is that we make a (small) change to the variable concerned and compare the result in the function of that variable to the starting point. With a single real variable there is only one sort of change that can be made, so implementation of the modern formula looks a bit over the top. But coming on to more advanced forms of differentiation, the 'derivative' is not even a single function but a matrix (called a Jacobian) or other multidimensional entity. On a historical note. Newton was basically a Physicist, who needed to invent most of the Maths he needed. He came to calculus of functions from the calculus (there are several calculi) of finite differences, which he invented. There are many formulae in this calculus which bear his name. He was doing this because he was interested in producing (interpolating) tables of values he needed and he was one of the pioneers of this subject. With the completion of most tables and the advent of computers, Finite Difference methods are not taught so commonly today. Leibnitz was primarily a mathematician, studying and developing the 'analysis' of his day. So he came to calculus directly from the theory of functions as it then existed as graphs drawn on paper.

Yes I made a spelling mistake, which I have corrected. Sorry, shadow.

+1

Yes and I would like to thank you for carrying on just such a discussion in another recent thread here about properties of materials, although we disagreed. +1 A good question, but not a simple one to answer. Swansont you stole my favourite line. Beecee conflates his meaning with reality, which is actually a different thing with a much more limited meaning. So to existence. English and German create new concepts by adding modifying words to 'existing' ones. English creates phrases such as concrete noun and abstract noun. German physically conjoins the words to form new words. The German method makes for shorter sentences but longer words, th eEnglish method makes for longer sentences employing more shorter words. The English method makes further modification easier. The whole of Mathematics is an artificial construct that did not develop from the BigBang (which I think is off topic here) yet mathematicians have a phrase There exists and even a symbol for it. [math]\exists [/math] The meaning here is that it is consistent with a stated collection of rules. For example There exists a solution to the equation x2 = 4 This is quite outside Beecees definition, but equally is not applicable to lengths of pipe, baulks of lumber and so on. We can extend this idea further to look at Strange's question from elsewhere. "Does Harry Potter exist?" Well the answer must be, yes in the abstract sense it is consistent with the construct of Rowling novels in particular and English literature in general. So what other considerations are there? Well I can offer the observation that something can be said to exist in reality if it can interact with other objects in reality, even though it does not possess some or all of their properties. For instance I contend that a shadow has existence, even though it possess no mass. Since Reg has mentioned donuts, A hole is the topological difference between a donut and a sphere.

What does the probability tell you? Why is the probability of getting heads in a coin flip one half and what does that mean? Once you have this clear you can move on to probabilities of continuous distributions.

Potassium permanganate and hydrogen peroxide or citriate salt or tartrate salt https://www.google.co.uk/search?q=potassium+permanganate+reactions&source=lnms&tbm=isch&sa=X&ved=0ahUKEwix8qvLlfLdAhWKW8AKHZ94CFkQ_AUIDigB&biw=1366&bih=622#imgdii=Yn_vxGDDlbd5zM:&imgrc=aJIIOLEzliBGuM:

Well yes of course it does, especially as this is a Science site, in case you hadn't noticed.

All you have pointed out is that you don't understand the difference between mass and weight.

The trouble with trying to be a clever clogs is that it is all too easy to outsmart yourself, which is what you have done here.

Please don't try to put false words I didn't utter into my mouth, or worse, false thoughts into my head. I simply chose not to bandy further words with you.

That is perfectly normal practice. What the OP means is that the average or mean (value) of a function over an interval (a, b) is given by [math]Av(f(x) = \frac{{\int_a^b {f(x)dx} }}{{b - a}}[/math] It is worth making the point that for waves symmetrical about the x axis this value is zero over a whole cycle, so we take the root mean square value instead. This is how the product of the function appears in the integral, except that for complex valued function squaring it will yield another complex value in general and we want a real valued answer. This is done by multiplying by the complex conjugate instead of itself.

Rather than castigate me for attempting to examine your particular brand of logic and philosophy, perhaps you should apply it to your own work. In your opening post you assterted the non existence of 'the scientific method', thereby in your own view removing any possibility of making a true (or false) statement about the method, however defined. So this entire thread is pointless and you are just prolonging it for the sake of argument. And it seems to be going round and round in circles, wandering further and further off topic. Therefore it must be time to drop the final curtain.

Then you will easily be able to demonstrate the falshood of uncool's statements. Assertion alone is not proof. +1 to uncool

I'd be quite happy to discuss the general philosophy of reality, truth existence material v abstract but that should be done in another (new) thread as it is really off topic here. So if you wish to discuss further, by all means start a new thread with these quotes, but be prepared for some suprises. I am fond of saying that Nature is more varied and suprising than Man has ever dreamed.

+1

Well there seem to be some references at the end of the article. Well done if someone has made solid helium.

A free body diagram does not include both forces in an N3 pair. If the wedge is regarded as fixed then it has two N3 pairs or one N3 pair and a moment pair.