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Comment Required power for damage (Score 1) 208

I wonder what you have to do to do sufficient damage to an enemy?

They talk about starting with 10kW lasers; Steel has a specific heat of about 0.5, so if you trained the laser on the target for one second, you could vaporise a little over six grams of steel (not counting losses from transmission through the air, reflection etc) I can see that if you're using your laser to assassinate someone from a drone, that's certainly enough to kill someone, but is it enough to destroy a truck or an aeroplane? Is the laser even capable of operating continuously for a second?

Comment Re:Enormous tax and administrative burdens (Score 1) 347

It's interesting that when this was first looked at in 1992 the specific reasoning behind not levying a 'use tax' was that the burden would be too high. It seems so me that if that's the case then there's probably scope to allow levying use tax on outside purchases if a way can be found to make the burden reasonable. For instance, could the court decide that use tax could be levied if there was a flat rate of use tax that applied to all items, whatever their type, if purchased from an out-of-state supplier? Also, I don't know what South Dakota's use tax laws are like, but it seems to me that the state might only have to prove that its use tax wouldn't create an undue burden.

Comment Please just be honest about it (Score 1) 819

I wish the gun control debate in the US could get beyond the 'do more guns result in more people getting shot?' question, and move on to 'Okay, so more guns means more people getting shot, but guns are important to us, so can we just discuss what level of people getting shot are we prepared to tolerate?'

It just seems so dishonest otherwise.

Comment Re:Far more abundant than lithium? (Score 1) 209

The world currently creates about 56 million passenger cars per year. A Tesla battery contains around 21kg of Lithium in it, so to switch all passenger car production over to lithium batteries, we're looking at in the order of one million tons of Lithium required per year, meaning production would have to ramp up by a factor of about 30, and we'd only have proven reserves for the next fourteen years.

There's something like 32 million commercial vehicles made a year, and if we assume they need a battery on average close to twice the size of a passenger vehicle then we'll need 2 million tons of Lithium a year, (a 60x increase in production) with proven reserves to last us seven years.

And that doesn't really figure in all the other places we'd start using batteries if we moved entirely away from fossil fuels.

Comment Data, motherf..., do you speak it? (Score 1) 93

There's a bunch of speculation going on in this thread based on personal anecdote... let's have a look at some data shall we?

Let's compare the ngrams of the words 'bespoke' 'customized' and 'customised' between the USA and UK:

USA: http://tinyurl.com/usabespoke
UK: http://tinyurl.com/ukbespoke

You can see that in both cases bespoke had its primetime in the first half of the nineteenth century, falling off and hitting its nadir at around 1980, with a resurgence in usage since then.

However, it's also clear that the usage of 'bespoke' is more common in British English than it is in American English, although not by a huge margin - current usage (in books) is about 70% more common in British English than it is in American English.

Obviously the huge cavéat here is that these ngrams describe how language is written in books, rather than how it is spoken.

Comment Re:I don't understand the opposing argument. (Score 1) 258

In central London where these routes are being constructed, you'll find very few "elderly, young or poor" driving anyway. There's already a congestion charge to pay if you drive in the centre and there's very few places to park. Very few people commute by car into the centre as there's almost no parking so the only people who do tend to be people who are sufficiently high up in a company that they can persuade their company to pay for a parking space. This is a city in which you can sell a garage in the centre for over £100,000. As a result, the vast majority of people commuting do it by tube, bus, bike or walk - or perhaps some combination. I get a train to London Bridge and then take a hire bike to the office. Most of the traffic I see during the rush hours is made up of:

* Buses
* Construction Vehicles
* Black Cabs
* Delivery Vehicles
* High-end hire cars

Comment Re:No KSP at SpaceX? (Score 4, Informative) 213

Firstly, I think SpaceX were trying to get away from parachute recoveries. The Shuttle solid booster rockets used to parachute down into the ocean, but the problem with that is that they need completely cleaning out and refurbishing between each flight.

Secondly, they would need more than parachutes to recover the first stage because it is travelling so fast when it separates (not sure of the exact number, but somewhere between 2 and 4 Kilometers per second). They have to do a retrograde burn to slow down enough to safely re-enter the atmosphere.

Comment Re:Old git speaking here... (Score 1) 942

The thing is, I'm not sure the vast majority of people do still use those imperial units. UK schools have taught in metric units for the last 40 years, and all food and drink (with the exception of draught beer and cider) has had to sold with metric labelling for the last 20 years. I'm 41, and although I have a good idea of what an inch and a foot is, I have no particularly intuitive feeling for a pound or an ounce, so I always have to the mental conversion to grams or kilograms first, and I grew up at a time when imperial measured labelling was more common.

Comment Re:This is not government policy (Score 1) 942

The thing I find interesting is that David Cameron is probably among the last set of people in the UK to have been taught any imperial measures in school - in fact he would have been eight years old in 1974 when using metric units in schools became compulsory, so it's possible he could have been taught both imperial and metric (Unless private schools were exempt from such rules, I guess).

Certainly anyone aged 44 or under in the UK will have grown up with the metric system in school.

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