It's also not enclosed and aerodynamic. The drag coefficient of a cruising (as opposed to racing) motorcycle with an upright rider is around 1.2. Compare this with a racing bike and a fully tucked rider that can get maybe .5 if they're lucky. A modern car is around .25. If you plug that into the drag equations, it comes up to a cruising bike with upright rider taking some 40+ HP to overcome the drag at 65mph, while a passenger car is more like 10HP at that speed.

The restaurant was just an example. There are still hundreds of ways someone could copy off your card even while you look and observe nothing wrong. Since you seem to be having trouble imagining your own scenarios, I'll give you another one: ever notice the security cameras at places of business focused down on the register? Those are there so the loss prevention guys can see the workers hands when the register is open and count the bills they place or remove if it comes up short. How carefully do you think they guard that video? A few minutes with security footage and liberal use of the pause button could get you plenty of card numbers and security codes. And ignoring any kind of technology at all, any person with a decent memory could steal the numbers no problem unless you exclusively swipe the card yourself (hoping they didn't put a skimmer on the machine at the beginning of their shift) while keeping black tape over the front to deter casual glances.

The bottom line is that if you give a business enough money to charge the card and a human handles the transaction, you've given at least one person all the info they need to charge it anywhere else they'd like.

Right, but why are you buying from sketchy startup e-commerce sites rather than the more established and well known places (e.g. amazon, newegg, etc.)?

I almost guarantee it was stolen from physically using it rather than a hacked website. You know when you pay for a meal at a sit down restaurant and they take the card into the back? All they need to do is photograph both sides of the card and they have all the info they'll ever need to go on an amazon shopping spree. If they wanted to get slightly more risky, they could carry in a magstripe reader (the electronics are tiny now, it could fit in a pocket no problem) and use that to make perfect clones of the card.

Hell, when I worked for a small photography company there was an order form that had people write their card info down as one of the payment options. We weren't trained to handle the forms with any particular security in mind. If I'd been inclined to steal card numbers, 60 seconds with my smartphone could have given me more than numbers than I'd know what to do with (plus emails, passwords, and PIN numbers during little league season since the form had the kids name and DOB on it and we all know how good people are at picking passwords).

It could even be stolen via someone putting a skimmer over the magreader and keypad at a gas station. I've seen pictures of the things in action. Most were built such that unless you know what that gas stations keypad and card reader should look like, you'd really have no way of telling if there's a skimmer or not short of prying at both the reader and the keypad to see if they come off.

This is why I always laugh when the less tech savvy individuals I know seem to think they're somehow being safer by never using their credit cards online. If the site is encrypted and properly secured (I'd assume the big ones like amazon, newegg, etc. are), and your computer isn't loaded with viruses, there's less danger using your card online just because the human element is out of the equation.

You've basically just described taping a magnet to a pole and suspending it in front of your car in order to make it go forwards, only in a slightly more complex way such that it's hard to see that's what's being proposed.

You seem to be forgetting that accelerating the particle towards A produces a backwards force. By the same token, diverting it sideways doesn't cancel out whatever backwards momentum it still contains, nor does hitting other particles to slow down (they hit other particles in turn and eventually transfer all the way to the back).

....that's literally the same thing? Every action has an equal and opposite reaction. If you transfer momentum while in the air, you're going to move back and continue moving back until you contact something (the bottom or opposite wall of the cage). If you were in a frictionless vacuum, the momentum would cancel as soon as you hit the opposite wall. In this case it doesn't transfer back again because of static friction.

Doesn't that only work because of static friction though? Bump hard enough to break the static friction and scoot across the floor, then move slowly when reversing such that you don't break the static friction on the way back.

You mean an AR clone? Rifles that fire more than one bullet per trigger pull (e.g., an M16) aren't up for sale to the general civilian population without jumping through some pretty annoying hoops and paying quite a bit of money. Here, I'll leave you with this nicely illustrated guide: http://imgur.com/a/zNc3a

You mean a 100 round magazine? They banned 10-round magazines for a while federally, and in a few states (california in particular) possession of a magazine with more than 10 rounds is now a misdemeanor. This means that if you live in california and owned a magazine with more than 10 rounds of capacity (the vast majority of magazine fed handguns hold more than 10 rounds) you must now dispose of legally owned property and replace it with 10 round magazines.