Casio

Why only AB? The two problems I forsaw were... 1/ I only have one force N acting, 2/ The whole point of the excercise was to establish the component force, which you've pointed out as the internal force. That is what I was always trying to establish. The force N acting along AB was always known, the problem was understanding how to work out the force internally (or along) BC to establish the internal (component) force. Hope I've made that clearer, sorry if I've confused everyone.

In the next post I will show how this is done using some simple example diagrams. I will also comment on where and why your information is correct or incorrect. Also, just in case some information NOT INCLUDED by me was overlooked, the Right Triangle is ONLY showing one force and half the calculations. In Vectors there must be two forces to find a resultant etc. I only included one. In a brake drum assembly, there are two shoes, one leading and one trailing. I only ever talked about forces acting on the trailing shoe using a Right Triangle. I also agree that force cannot turn corners, but maybe the confusion was around two areas of my concern that may have been misinterpreted? 1/ The applied force of 102.3 N travelled along AB ONLY. There then is a frictional force created (uP) This frictional force amounts to 32 N. I didn't know whether in my calculations to include it or dismiss it? 2/ The force (I said) along BC is NOT redirected from AB. 3/ The force I calculated along BC being 81.1 N I am referring that force to or calling that force the "Component" force. What do I mean by component force! The brake shoe is metal, the lining material is a mixture of compounds and resin. The frictional force acting is 32 N. This force is the force on the shoe material and the rubbing surface of the brake drum. This frictional force 32 N being pushed on the brake drum is a calculated force from the 102.3 N appllied force, but I think is a seperate force. The force acting along BC I refer to as the component force. This is what I am trying to establish as the force building up inside the brake shoe itself. So Newton said, to every action there is an equal and opposite reaction, hence, the force applied at B towards C is the component force and I calculated that as 81.1 N. Now to achieve that force, the pivot at the heel of the shoe must maintain the shoe in that fixed position, therefore a reverse reaction is created equal and opposite the applied force. The shoe has now got an internal force present of 81.1 N. So, how dense does the material a shoe is made from have to be? If the material is too thin the shoe will distort and break. The component force calculated is to help interpret what force what thickness material can cope with without distortion and damage. Hence why I was thinking about vectors and forces to calculate the component force!

I didn't think the conversation being carried on was necessary. You pointed out that what I said was nonesense. I thought that if you'd ofunderstood what I was trying my best to explain, then you might of returned with some constructive suggestions and or applied math to show how its done, but you didn't so I took it you didn't understand what I was trying to do. I appreciate it difficult to interpret people and ideas on such forums as these, but at least I tried. If it loads I've now included a diagram.

Ok thanks for your input anyway. I'll need to find an engineering forum that has experience in these areas of expertise. Ok I've managed to work out how to do it. I've got a force of 102.31 N acting along AB. I wanted to work out the force acting along BC and CA. I knew that some losses must occur due to the angles the forces had to pass round. This is how it is done... F Cos theta = 102.31 N x cos 37.59 = 81.1 N, and F cos theta = 102.31 N x cos 52.41 = 62.4 N Now using Pythagorus we have... c = square root a^2 + b^2 c = square root 81.1^2 + 62.4^2 c = 102.32 N In conclusion... Force AB applied was 102.31 N, the two remaining forces acting after the acute angles are; 81.1 N and 62.4N That's good enough for me to give me some guidance, and I'm seriously NO expert in this.

Thanks for your reply. The triangle is imaginary and is not similar to another triangle. I'm no professional in this subject, but another book I've researched suggests I should have posted this problem in the Statics forum and not the maths department. If I can find away of posting my drawing I'll do it as soon as I can, but I think you could also get a good general idea of my request by drawing a right triangle on paper yourself to give you the picture I'm referring to. The specifications... Right triangle. The 90 degrees angle MUST BE at the right corner of the horizontal line, i.e. __________________Here. Then follows the vertical line downwards, i.e. | This line touches the horizontal line marked "Here". That is the 90 degree angle point. The horizontal line length is 10.5 cm. The vertical line length is 13.5 cm. The line that represents the hypotenuse is 17 cm. The triangle has acute angles, the top left is 52.41 degrees and the bottom angle (sine) is 37.59 degrees. My problem... An applied force is present along the horizontal line from A to B. A is the 90 degree angle. B is the 52.41 degree angle to the left. When the force of 102.31 N is passed along the horizontal line from A to B, the line changes direction along BC, which is the hypotenuse, which then changes direction again by 37.59 degrees along CA to the 90 degree start point. The force must change its magnitude when it changes direction. What I'm trying to find out and learn is how to use the acute angles in the math to calculate the new forces along BC and CA. I hope you understand what I'm trying to do!!

No, the triangle is representing forces. In this right triangle, there is only one force N applied. This force then meets and equal and opposite force at point B in the right triangle, and then that force changes direction by 52.41 degrees and travels along the hypotenuse BC, before changing direction again by 37.59 degrees back to point A which is the right angle 90 degrees, where the applied force starts. Because only one applied force is known, in my understanding, until the angle 52.41 degrees is taken into consideration to change the direction of the force applied, then the force along BC cannot correctly be calculated. So the engineering book I'm reading advises to measure the length of the sides of the triangle and multiply that length by the force applied to justify the force acting in that direction, such as the force from AB = 102.31 N times 10.5 = 1074 N, and then the force is applied again along BC = 102.31 N times 17 = 1740 N So by just calculating two sides, the applied force is increasing after changing direction of 52.41 degrees. I just can't accept that the method used is correct? Forces changing direction like this to me I'd think should reduce in force, not increase?

While that maybe true in what you say, it however doesn't help with the orginal question asked!

First answer, multiply force x distance to get a force? Your not creating a force doing that, you've already got the force, its just increasing along the line of action. Strickly speaking yes in the SI Units the length should or could be metres m, but equally so the units cm are also used. Common sense must prevail, if then your measuring a football pitch, by all means use metres m, but if your measuring something approximately 50 mm long, then I'd of thought using either mm or cm would suffice. The engineering book is using cm so I kept with that unit of length. This is not homework. I'm simply reading at home in an interest I have based on my job I do. I'm nearly 60 years old and have no interest nor energy left for speed chalk board exercises that also envelope many mistakes.

I have a right angle, the 90 degrees angle is at the top right corner. A force is applied along AB. AB is the horizontal line from the 90 degree corner marked A to the left marked B, with a length 10.5 cm. The force along AB is 102.31 N. The force AC is the vertical line of action measured at a length of 13.5 cm. The hypotenuse final length BC is 17 cm. Hope your with me to this point! According to a engineering book I've read that includes the methods for calculating the Traingle of Forces, where two or more forces are known, the side lengths of the triangle are measured and then multiplied by the acting force to record the results, however, either I'm missing something in the writing of the book, or information is missing! By example... The force acting along AB is 102.31 N. The length of AB is 10.5 cm. Therefore 10.5 x 102.31 = 1074 N Now the line of action changes direction from AB to BC, and this is where I'm questioning the book maths. The length of side BC is 17 cm, therefore 17 x 102.31 = 1740 N I could carryout the same procedure with the remining vertical force, which records 1381 N. What I questioning is this. The book example is using the Triangle of Forces Rules, but nowhere does the written instructions in the book take into consideration that these forces have changed direction, at angles of 52.41 degrees being angle ABC, and 37.59 degrees at angle BCA. Am I missing something here? I'm sure the angles should be included in the math!!

Given the Almighty is supposed to be the Alpha and Omega and know or understand everything, his wisdom has clearly proven that it is only as good as his weakest link.

From what I understand God put the serpent into the garden to watch over Adam and Eve. Although they were perfect that does not mean they knew or understood everything, they had not had the time to gain long term experience, which is not much different to us now. We all fall foul of some people who take advantage of us and we get what I call the short straw, which hopefully we learn by our mistakes not to get it again. It is said that Eve was deceived by the serpent who presented himself as a snake. Some talk about the apple, but I think it is more to do with understanding desire, the knowing and wanting something, so maybe it was more likely the serpent said something to Eve that caused her to take the bate. Presenting this bate (whatever it was) to her husband Adam caused him to agree with her which is where the problem with God arrived. God knew something was wrong at that time because Adam and Eve were said to be hiding in the trees, because they had become aware they were naked. Do children growing up not go through this very same experience, I think we all go through it. The problem I have here is that we all die because through Adam sin past to all men, however conversations I've had over time people tell me that Eve was deceived. Maybe that could be true, however if I tricked you into something that would put your life in danger of dying, would that be your fault? If Eve was not to blame or partially to blame, she would still be here today, but she is not. It is also said that a balance had to be created to allow imperfect humans to co exist, so Jesus was sent to earth as a human sacrifice for all those who exercise faith in him. Where is Jesus our mediator today? He died over two thousand years ago, he made a name for himself but where is the real evidence that God or Jesus are real? It is said that the bible is a book of knowledge that tells us about diseases and how to live etc, but take covid-19 now, did God instruct worshipers to stop socializing? No that was carried out by our governments, who took advice from scientists. Where is Gods involvement in the current world pandemic? Many and many questions but no evidence of a real world invisible God or Jesus.

As I have advised previously about this subject, I'm no expert or deemed to have any professional understanding of this subject, but a research medical journal I read advised back in 2017 about corona virus and trials that were being carried out back then. You start to get to a point that you hear people on the TV in the medical world with a lifetime of experience trying to advise you things that they are being told to keep their mouths shut about. Two doctors on the TV recently tried to speak out about this virus and one doctor was told to shut up and could not say what he wanted, and the other doctor had contracted the virus and since has past away. Recent information I've read had this to say about the corona-virus going back as far as 2017; Ivermectin Lab tests performed by Australian researchers showed that this anti-parasitic drug stopped the coronavirus growing in cell cultures within 48 hours. This widely available drug has already been shown to be effective against other viruses including HIV, dengue, flu and Zika. Ivermectin is already approved by drug regulators and is widely available although it would have to be trialled in patients before becoming an accepted therapy.

I'm no expert in this subject at all, and if it were not so affecting humans to the degree it is worldwide, I'd probably of never had an interest to look in on the subject at all, however, that said, I think that some serious questions must be raised to ALL world leaders after this COVID-19 is resolved, if it can be resolved as Russian indicate that it might never be resolved.

A lot is now being done where schools and business are closing although some business are doing their best to keep open and active. In my trade the government control us and are currently advising that we can't stop Statutory testing and examining motor vehicles. Today I've read about some businesses saying that they are asking customers to turn off their heaters and remove any items in the vehicles like food stuff, cans, cups etc. How serious should this vivid 19 be taken as a working class person dealing directly with the public!

Here is a Government UK link to statistics etc regarding the virus. https://www.gov.uk/guidance/coronavirus-covid-19-information-for-the-public#risk-level

One should always try to live a life as relaxed as one can in the circumstances. No matter what everybody might think or believe, nobody has complete free will. What you can and can't do will come from various sources, such as one's ability to understand what one might want to do in their free will, and a main one these days being the society we live in, which does control what we can and can't do quite a lot nowadays.

Thanks for your input.

Was the earth always at an angle or was in knocked onto the angle it is at? I'm told today that if the earth was not at its present angle, that we would not experience the changes in the weather and climate, is this true?