studiot

The original question asks for an explanation of the difference between an image and a likeness which is a technical question. This threas seems to me to have now taken a definitely proselytising turn. Consider your left hand and your right hand. The are alike or they have a likeness. but they are not the same. They are only an image in a mirror.

I'm still waiting for the explanations of both the earth's magnetism and superconductivity. All you have told me so far is that they are different, which I agree with.

USPS ???? For the past week or so the posties around here have been delivering dressed as santa. It is some management iniative to promote the Royal Mail. And furthermore Sunday last a whole posse of bikers in santa costumes rode up to the local hospital ro deliver their annual gift to the children's wing. 😄

Well How am I supposed to know that your last line is different from the one above it. Or are you telling me that there is no connection between refraction, reflections and interference ? what about all the other line with 'and' in ? This is very poor scientific writing, in my opinion.

Shame on you you've shattered my illusions if you are trying to tell me that the tooth fairy and santa claus do not exist. If the latter who has been delivering my mail this past week ?

I am the centre of the universe and have been since I was a baby - a fact well known to my parents. 😄

Yes good idea. In what way is the Earth's magnetic field related to superconductivity ?

lol Google was unable to translate. Since you can obviously do this please do so.

Thank you for that extended reply. Was that from an AI ? I ask because LLms do not read the message of questions put to them but are constrained to display an answer, just as their forerunners, the digital display in instruments and calculators, was so constrained. Unfortunalely you repsly does not even begin to offer the explanation I asked for. Note I did not ask for proof of anything I asked for an explanation .

Did you read the rules at SF about posting discussion material lately ?

Where was it posted ?

I'm sorry, was it on the previous page or did I miss it. ? Where is the maths in all this ? Lot's of pretty pictures and idol worship, but where's the beef ?

When your original post is fit for other members to draw from perhaps you would like to explain what underlies your link between gravitation and inertia. The two are currently regarded as different independant phenomena and the fact that, as far as we have been able to determine, they offer the same values is just a fortuituous accident of the unverse.

I would have thougth any parent or grandparent would have first hand experience. Facilities for games, school dinners, practical subjects like woodwork, science are regularly being sold off by schools around the UK and have been for some decades. Some universities now use circuit simulation only instead of hands on electronics, mechanics etc. Or else, like Exeter they have simply closed the Chemistry department.

With the accountants and centralists now firmly in charge of education would members like to comment on the trend to reduce or even remove all practicals from the curriculum at all levels from primary to university. How is this impacted by the current expanding crop of 'demonstartion videos on Ytube and the like ?

Yes of course, but just be glad you are studying under the MKS metric system. There is also a unit of force called the kilogram-force or alternatively kilogram-weight. https://en.wikipedia.org/wiki/Kilogram-force This short tutorial may also help BBC BitesizeWeight and mass - Forces and movement - KS3 Physics - BBC...Weight and mass are very different. Find out more with BBC Bitesize. For students between the ages of 11 and 14.

I understand and sympathise with your need to obtain marks. Perhs you could discuss the issues with you teacher ? Remember I said you have to start somewhere, you can't do it all at once. So teachers will not tell you everything at once, (I haven't done that either) but good teachers will take the time to explain further to those, like yourself, who are interested enough and intelligent enough to know a bit more. Mass is one way of measuring the quantity of matter in a body. This definition becomes important when studying forces and dynamics.

Then I agree with you that the question was poorly worded, especially as it was an exam question. I also agee that it was not clear what force they were asking for since you have evidently been taught to distinguish. However there is also not enough information to answer the question since I would assume (as any schoolboy and KJW) that the object was on Earth since we are not told otherwise. KJW's diagram relies on gravity so there must be a third force acting on the spring balance if we take that as the object. This, of course would be the weight, W, of the balance . But KJW asked for the reading not the force acting, and there is a difference. Since you have come across vectors can you say anything about the vector sum of the two or three forces that are acting ? Did you also understand the difference between the two equations I wrote for you? Have you come across the equation W = mass x g = mg ? Finally can you think of another distributed force ? This becomes important in situations where no one in their right minds would say that a pair of equal and opposing distributed forces mean zero force on an object. Hopefully this discussion is helpful.

Thank you for responding, with that useful information. +1 I asked because I am trying to be careful to avoid messing up your programme of study. You have clearly picked up on something, perhaps as swansont said it was just a poorly worded question. Were these the exact words of the question and nothing else ? +1 to KJW for the excellent sketch, I for one have not seen before, but so obvious when posted. So we come to that word 'vector' that I avoided, but both the other responders used. Forces are usually introduced (in basic Physics) before vectors are introduced and often used a lead-in to vectors. Have you come across vectors yet ? In my day forces were introduced by way of a spring balance, like KJWs picture. The whole class has a competition to see who could pull out the spring balance the furthest. Vectors were not introduced until advanced school physics, and later still in Mathematics where they were introduced by way of velocity. Yes "Force is a push or a pull" is a good start. The thing is that there are several thing you need to know at once about forces and your teachers have made a good start with with contact/non-contact and balanced/unbalanced. The spring balance is good because it shows any Force has four particular important characteristics. A line of action - more particularly a straight line of action. A magnitude or numerical value. A direction along that line. A point of application. Vectors are more general and do not necessarily have a point of application, as for example velocity is a vector without a point of application. I will add one more thought to your contact/non-contact idea. In order to represent all forces in the format of my items 1 - 4 we also distinguish body forces such as gravity which are distributed throughout the body and introduce the 'point of action or application' as a 'centre' the COG or cnetre of gravity in the case of gravity. The force of gravity is often excluded, either deliberately or just forgotton, as in the case of the question "What is the force on a book lying on a table ?" With the foregoing the student is well equipped to study lots more mechanics including Newton's Laws, equilibrium, net force', ' resultant force', 'total force', and so on. ~With this study will come some mathematics - equations and the like. Depending upon the format of these equations and the mathematical sign conventions used your original question can be presented in several ways. Assuming no other forces acting (excluding gravity) Forces from the left = Forces from the right so your body is in equilibrium. 150N to the left = 150N to the right Alternatively with the convention forces to the right are positive The sum of all forces = 0 so your body is in equilibrium. -(150N) + 150N = 0 Does this help ?

Without seeing the question it is impossible to tell. Strictly speaking neither zero nor 300 N can be correct but there must be more to it that meets the eye. Where was this question and what are you studying ? What do you know about forces ?

Had I seen that report I could have said I left that for you.

The mathematical term 'group' (originally from the german) is just not appropriate for this purpose. There are other group axioms which the model does not comply with.

It appears that Ash trees are evolving resistance to the dieback that has swept Europe. BBC NewsShoots of hope for Britain's cherished ash treesScientific evidence suggests ash trees are ‘fighting back’ against a deadly disease.

But sometimes he is piercingly perceptive and I for one wish to encourage that side of him. No attack, its just properly conducted discussion. However if you are using a mathematical group you do not have the luxury of a point of view. Element uniqueness is part of the definition. The real number form an infinite group and every one of them is different. My query, and I believe that of dimreepr, was that the OP has claimed that repetition (or copying) must occur because the universe is infinite.. This is not so. Perhaps there is confusion between Cantor's definition of an infinite set as one in which each subset can be mapped one-to-one to the entire set, for example the interval (0, 1) contains the same quantity of points as the whole real line but it is in no way the same or a copy.

Please explain the purpose of your enquiry. Is it for cosmology as has so far been assumed or the alternative geological hypothesis about plate tectonics being due to the Earth shrinking, or what ?