Recent content by E_Q

It was all one sentence o.o I'd like to point one thing out: constant speed doesn't always mean no acceleration. For example, circular motion - there is always a centripetal force (and hence acceleration) on the body towards the centre, but as it is always perpendicular to the body's motion...

et voila

Sorry D H, ultra-bad phrasing. Cheers Mark, you must have got used to my flawed writing ^^ @AllyScientific: The equation you just wrote didn't need i in; (-x)2=(x)2. So there should be no surprise. You're forgetting perhaps that i=√-1; you've sort of cheated as your answer -1 is real, wheras...

grrr I'd love to use the phrase "you know what I mean" but I'm sure you'd argue what I meant was wrong :-p. You're right, but I'd not heard of the term "relation" before, so I just stuck with function ^.^ The loose use of the word function is because that's how my maths teacher says...

Think I've grasped the idea now. x2=4 x=±√4 x=±2 But if you are simply presented with x=√4 then the only solution is x=2 as it refers only to the positive root. It's a mistake that often doesn't get picked up on that √4=±2, as if you then square both sides you lose the negative...

Quite right. Loose talk, not mathematical. Yes I did think of this, but didn't realize that it meant the graph was invalid without saying x ≥ 0. Correct me if wrong: y=x2 is a one-to-many function, which is allowable, but this means it cannot have a function inverse as that would be...

Why do the rules of surds not apply for negative numbers? I've never head this before. And it appears to hold true, it simply provides an extra solution which is incorrect, as well as the correct solution. I'm similarly confused on your next point; √1=±1... Take the inverse, (-1)2=1 and 12=1...

I discared neither value, that's why I left the ± notation. This is the answer I wanted though; i3 represents a transformation of the point (1,0) 270° anticlockwise (like you said multiplying by i rotates 90° ACW, and i3 is equal to 1.i3), which of course becomes -i on an argand diagram...

When doing FP1 ages ago I discovered a way to seemingly get i3=±i, and since then nobody has provided a proper explanation for why the positive solution is impossible. Standard solution i3=i2.i =-1.i =-i 'flawed' solution i3=(√-1)3 =√(-1)3 Using the laws of surds, √a.√b=√ab =±√-1...

I think aero51's finished this thread really, but I'd like to explain a bit more into it (or perhaps reword it more simply). As he said: Vtip=ωL (ω is angular velocity, radians/second) But really, in the context of this question just think of V=ωS, With S being the distance from the hub to...

First, draw a diagram! Like you say, for the system to remain in equilibrium the forces (so the system doesn't accelerate) and the moments (so the system doesn't rotate) need to sum to 0. Like nvn said I would start by summing moments about support 1 (remembering to consider the reactive...

What level are you looking for? If you're still doing A-Levels (as am I) then I wouldn't worry too much about the content, just so long as it's a book that stretches your engineering mind. Engineering Science, Oxford University "At present we do not produce a reading list for students applying...

I would strongly recommend "Structures: Or why things don't fall over" by J.e. Gordon (https://www.amazon.com/dp/0306812835/?tag=pfamazon01-20) Though it doesn't entirely fit your areas (perhaps more civil or material) I loved how Gordon explained a concept then gave several real-world examples...

^ haha! I'm going to come in late and suggest that instead of "Praise" or "Thanks" just a simple "+1" button could be used. This could add towards a reputation counter. I say this because if you see a good post, you aren't particularly thankful of that post, but you might be impressed and want...

I would say that this is because magnets are easy to manipulate mechanically, and any movement of a magnetical field entails a movement in an electric field. Most of the energy generation methods used on a large scale involve a change of energy from one form (chemical, mass, kinetic) to...