If that one would be actually possible, it would make baseball worth watching.
From distance.
With sunglasses.
And with a solar popcorn oven.
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…and aimed it at Jamie - they could call the experiment The Walrus And The Punter
“A reaction drive’s efficiency as a weapon is in direct proportion to its efficiency as a drive.” And vice versa.
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compared to a truck at rest, 55 miles per hour is approaching the speed of light.
the journey of 186,000 miles per hour starts with a single step (per hour).
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c = 671,000,000 mi/h = 186,000 mi/s
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Unless you’re in the financial sector, here in rural Connecticut life just happens slower.
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The only issue there is the acceleration it would subject you to. (Actually, I just did the math, and it should work. If we assume a 40ft bus going 40mph, and the cannon goes the whole length of the bus, you could do it with only 1.3 gravities, which isn’t too bad at all. Until the bus driver has to hit the brakes while someone’s in the cannon, that is)
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You beat me to the calculations. 
That would not be a problem. If we assume a coil gun style of cannon, in other words a linear motor, the cannon could auto-adjust the payload velocity and the acceleration to the payload may be even a bit lower as the speed of the vehicle at the moment of passenger unload is lower than at the moment of starting of the operation. (Or maybe not? Tried to imagine that and got a headache. A well-controlled linear motor is a must anyway, though, for a variable velocity vehicle.)
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To get the full benefit of not having to slow the bus, you need another linear motor to grab people and accelerate them to bus speed if they are standing too close to the bus non-stop.
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Series 8 Episode 3
You could throw Larry Niven out the back of the truck and he would fall straight down, but if you try it with a photon, different things happen.
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Think about it some more and you are better off with just the linear motors, without the bus.
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I am amazed they got it so perfect. That ball falls almost straight down. I mean, 50mph ~ 22.2 m/s? Looks like the truck and cannon speed were easily within 0.5% of one another.
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This is awesome, but to be a slight curmudgeon I have to say that the gif has a problem.
With the changing speed-up then slow-down then speed-up of the gif, it gives a false impression of the movement of the ball. Specifically, it perpetuates a misconception that things shot in a parabola really do “hover” at the top of their arc.
This is a very common misconception. If you ask a kid (or most adults) what would happen if you put a gun down by the floor – i.e. just an inch off the ground – and shot it sideways, many think that it could reasonably take a second for the bullet to hit its target. Instead it only has as long as it would take you to drop of bullet from an inch off the ground.
This gif makes it look like there’s some invisible force that’s holding the ball up for a few extra moments. And the reason that it’s bad is that you look at it and say “oh yeah, that makes sense,” because it matches your prior understanding.
(And I’m speaking of a misconception that the ball will hover for longer than the natural acceleration of a ball being dropped.)
Besides playing it at the same speed the whole time, which would allow us to see the normal acceleration due to gravity, another nice touch would have been to have someone off to the side dropping a ball at the exact same time.
/curmudgeoning
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Beautiful relativity demo. here’s a clock with a second hand that doesn’t get anywhere. https://vimeo.com/53100468
No, his famous alleged experiment had to do with gravity, not total velocity vector.
He performed more than one nonalleged experiments.
You led me to a thought.
What about the decelerator not being part of the bus, but the bus stop being mobile? The bus drives by, the bus stop accelerates to its speed, joins the bus, people move in and out, the bus stop disconnects, and drives the rest of the circle back to its starting position, where people disembark and new ones move in.
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That’s practical.
