Digsy

If the battery has been deep-cycled already (i.e. let go completely flat for whatever reason) then you can kiss it goodbye. Standard batteries hate being deep-cycled. When my alternator was on the way out I got a brand new battery and of course it went flat within a few days and would not accept a charge after that.

Does it contain a fully closed surface?

STP is a solid file format already so either the file does not contain anysolid bodies or it is not translating correctly, which can happen with cOmplex shapes.

OK, no malice intended here at all, but I'll explain why I find this so funny and why its so relevant to the question The question describes a mechanical arrangement of the plane on the conveyor. As has been discussed at length in this thread by the "plane takes off followers", there is no way that the arrangement described could actually prevent the plane from moving forwards. However, the "plane doesn't take off faction" circumvent the realities of the experimental setup and jump directly to the assumption that the somewhat ambiguous wording "the conveyor belt is designed to exactly match the speed of the wheels, moving in the opposite direction" means that the plane cannot move, even though there is no way this can actually be the case. No one is disputing that planes need airflow over the wings to take off, but that is one step after the fundamental question of "can the plane actually move?". The people who look at the mechanical system know that the way it is described cannot possibly stop the plane from moving forwards, even if the person who wrote the question actually intended to imply that would be the case. Therefore they interpret the wording of the question literally and conclude that the plane moves and therefore eventually takes off. However, people who focus on the statement about the conveyor moving in the opposite direction assume the plane remains stationary as a boundary condition for the question, and rigidly stick to this viewpoint regardless of the literal mechanical explanation. Therefore, the "plane doesn't take off faction" are basing their conclusion much more on an interpretation of the question that the "plane takes off followers". Substitute the word "interpretation" for "belief system" and you will see why the "try religion" meme is so ironic. Those who think the plane stays still are those following a religion, not the ones who think the plane moves and therefore takes off. So your post was precisely what this question was designed to highlight, but you pretty much hoisted yourself by your own petard.

^^^^ Anyone else loving the irony of Mark's post, and the attachment?

OK to save this eating up all the server space like it did last time... The question isn't really about physic at all. It is deliberately badly worded to be ambiguous and to demonstrate how people interpret things in different ways, and once they choose an interpretation, how difficult it is to convince them otherwise. The question isn't clear enough about what it means when it says the conveyor belt moves "at the same speed as the wheels". Which part of the wheels? The outer radius of the tyre (i.e. the tangential velocity of the wheel), or the forward speed of the axle? Many people assume it is the forward speed of the axle, and then assume it follows that this means the conveyor belt stops the plane moving forwards. However the question does tell us that the wheels move. If the wheels didn't move, then there would be no speed for the conveyor belt to match. If the wheels move, then the plane is moving. In reality there is no physical mechanism that can act through the wheels to decelerate the plane once it starts moving. At best the conveyor will change the reative speed between the "ground" and the plane, and therefore speed that the wheels rotate, but it cannot affect the forward speed of the plane. If the plane is moving, the wings will generate lift and the plane will take off. This is the mechanically correct answer to the question. However, if you accept the boundary conditions of the question as "the backwards motion of the conveyor cancels out the forward motion of the plane" (despite there being no practical way that this could ever happen), then no, the plane would not take off.

Incidentally, if you are looking for another badly worded question...

It could also be that as long as you get the sums you attempt correct, it doesn't actually matter if they are the right sums, or if they actually correctly answer the question or not, but that's probably a dangerous assumption.

If you run on a treadmill you are propelling yourself forwards with respect to the treadmill by pushing against the surface of the "road" which itself is moving backwards at the same rate. A jet aeroplane moves itself forwards by pushing the jet exhaust against the air behind the engines* (which itself remains stationary). Your analogy would only hold true if the plane was being driven down the runway by its wheels. *edit* more correctly, pushing against the air and expelling exhaust mass backwards to create an equal and opposite reaction forwards through conservation of momentum, as stated by pedro below.

It will match the speed of the wheels, not the speed of the plane. Assuming the conveyor is moving backwards, it still cannot physically move the plane backwards, or even decelerate it, by acting through its tyres unless the brakes are on or the bearing friction is extremely high. I say assuming because that's what everyone (including myself) has been doing. However I'm not even sure that's correct anymore. Looking at the attachment: In step 1, the plane is at rest on the runway. In step 2, the engines are on and the plane moves forwards by a minute amount. The tyre contact patch is actually moving backwards with respect to the plane. The marker on the tyre stays more or less above the marker on the conveyor (assuming the plane only moves a little way). In step 3, if you interpret the question literally, the conveyor has to move forwards, as it is matching the speed of the wheel but in the opposite direction. The conveyor rotates the wheel back to its start position where the two markers line up. However the wheel centre has still moved, therefore the plans has moved, therefore there is airflow over the wings, so it will take off. Looking at it this way, even the wheel bearing friction ceases to be a potential issue as the wheel never really rotates at all. If they conveyor moved backwards, it would be moving in the same direction as the wheel, doubling it speed of rotation but still not actually moving the plane itself backwards. Within the context of the question steps 2 and 3 would actually happen simultaneously.

I'm on the wrong side of a couple of pints of Guinness so its taking some time to sink in, but if you look at questions 1a to 1d the information needed to answer them is given in the same order in the paragraphs above. I think what they want is for 1b to include all the weight (i.e. with rucksack and everything) but just be the energy for the act of lifting the vertical distance calculated in 1a. 2a is a simple calc for the energy to stay alive without doing additional work. 2b is set up for 2c, calculating 10% of the basic "stay alive energy" which is the extra required to climb 500m. 2c itself is a let-up as they tell you how to do it, rounding up to the nearest 1000m to save on complex division problem. 2d is just calculating the "extra energy" required to survive when walking with a rucksack (+10%) over snow and ice (+10%) again using the answer from 2b. What is not clear here is whether these extra allowances are also dependent upon the height being climbed, or a constant. 2e is the sum of everything calculated so far. Anyway, I recommend you don't let your sister's girl have a couple of tinnies before she takes on the question

Its certainly complex, but as far as I could see from reading it through all the information is there to answer the questions. Some of them are not very well worded, however. For example, 1b does not specify if hie "total weight" includes his rucksack or not but the information suggests it would. Then 1d specifically mentions the rucksack as a separate item so it might be tempting to go back and remove the rucksack allowance from the answer to 1b and calculate it separately. 5b is the only part which is really open to interpretation and not strictly down to a calculation. Its been 34 years since I was 11 and for 24 of those I have been a professional engineer so I find it hard to look back and remember if I could have answered a question like this when I was 11. I do recall questions of similar complexity in my O-levels, though, which would have been 4 or 5 years later, so I suspect I would have struggled with this at 11. Then again I have no idea what an 11 year old is taught these days.

Best answer yet

If you wanted a more "OEM" solution you could fibreglass a Bighead nut onto the bumper: https://www.bighead.co.uk/the-original-bighead/#our_range

OK, if you have access to a machining centre I guess you can absorb the cost, but big items still means a lot of swarf on the floor. Was just wondering about m/c from solid versus 3D printing. Which would probably be 4 figures for something like the engine cover.

Just out of interest how much would it cost to get something that size chewed out of a single lump? I'm talking about the cost for the actual machining time and setup.

Low to mid range. Nearly all road car engines nowadays are what you would call "downsized". i.e. its more common to see a turbocharged 1.5 litre doing the job that a 2.0 NA would have done 5 years ago. Advances in technology means that most of the throttle response of the older 2.0 NA has been retained. We are now entering the realms of "extreme downsizing", where engines will be expected to perform like units twice their size and more, but this comes with the added penalty of unacceptable lag as the turbos get bigger in relation to the engine. The eBooster is really just one of many extreme downsizing enablers (like twin-charging or R2S / R3S), but most of the tech targets the low end.

Not really, although they are set up in series. During the throttle tip-in the larger turbo isn't really generating much boost pressure, and the compressor wheel is large enough that at low airflows it doesn't create a restriction so it is almost like it isn't there at all. As soon as the main turbo comes on song the eBooster will switch off and bypass. Its not clear if this is a 12V unit or higher. There were some 12V units kicking around about 10 years ago but Valeo are first to market with a 48V unit in the Audi Q7. The 12V units didn't have the puff to be applied to anything other than very small cars unless you ran silly currents. Also, these things overheat - and fast, So they are only good for a few seconds at a time, so they are only good for improving transient response. I think the Valeo production unit is air cooled, but they have a water cooled version too which might be good for longer duty cycles.

As above just let the police and insurance handle it. They'll be up for driving wihout insurance and leaving the scene of an accident, not to mention assault, even if their mother won't report them for taking without consent.

That sounds dodgy as hell. Get that agreement in writing, or I bet they back away from rapidly it when they find out how much it will cost. Strictly speaking, they should be notifying their insurance of any accidents regardless of whether there is a claim or not (like we all should, but obviously no one does). I would expect a company to operate more "by the book".

Not really much point suggesting property unless the OP has enough spare cashflow to fund a second buy-to-let mortgage (less rental income after tax) as well as this £10K burning a hole in his pocket

I have been putting my savings into premium bonds for just over a year now as an experiment (which I plan to finish when the American elections / Brexit / zombie apocalypse is all over and things settle down). I track its performance as if it was a regular savings account, earning interest. What I can say is that the published "growth" figure of 1.25% is roughly correct - but you need to be in it for over a year for the maths to demonstrate that properly, otherwise any initial winnings in a short term skew things and make it look much more profitable than it really is. I've been hovering around 1.25% for several months now. Not exactly earth shattering, but an order of magnitude above what my bank is offering. I have almost the maximum invested and it is now very unusual for me not to get at least £25 a month. More recently, I have been getting larger wins (£100 or £75) one month and then nothing the next. However, the larger prizes continue to elude me. I don't see it as long term investment - just a zero risk / low return alternative and a bit of fun for a couple of years. The equity funds I took the money out of were making >5% annually so I need to get back into that as soon as it is safe to do so.

I looked into this a loooooong time ago when I had a weepy rack which (thankfully) cured itself. As alluded to above, getting a professional; refurb done will be mega bucks, and also you would probably have to send your rack off to be repaired and wait for it to come back. In the past I have bought reconned racks for other cars on an exchange basis, but Supra racks are rare enough that I found this approach was not practical. I *think* I even have the complete strip down and rebuild instructions for the Supra rack and I sriously looked at installing the seal kits myself, but I found that there are so many special tools involved it was a non-starter as a DIY job. Mind you, at the time I needed the car on the road, so if I had alternative transport I may have given it a go. In the end I found a 2nd hand rack locally, but as my leak fixed itself it sat in my garage for several years before ending up in a skip!

The lower corners of the rear window are one of the very few areas that Supras are prone to rust. Could be because the drains get blocked, or the window seal itself perishes.

Would this be a large capacity card than actually turns out to be a much smaller card with a firmware hack that makes it report its size as much larger than it actually is? I've heard this is common with Chinese cards and USB sticks. Might explain why your card is suddenly full and the files corrupted.