Mad Rocket Scientist

They must be confident in their braking, this is even more than 1 vehicle/sec. Does anyone have any resources on how braking and friction works in cars? Is deceleration constant with computer controlled braking? I'd like to run some numbers on this. The first question is what kind of accidents are possible in a tunnel with self-driving cars, and how fast they would decelerate the vehicle. Anyone have any ideas? If the above figure is within an order of magnitude of the final cost this would be an amazing boon to any underground project. This makes it sound like there may be some convergence with subways for loop, which brings up an interesting question in trying to judge whether this would be better or worse than subways: How should success of a transit system be measured? People using it? People's happiness with it? Cost to the user or the operator? Environmental impact?

787 Gap of 14!

769

I'm not sure, Elon Musk said "retractable" on twitter. And putting them on and taking them off constantly seems like a nuisance.

So no more sleds? I guess it makes sense to use the motors already on cars, but that means no gasoline cars. I wonder how the retractable guide wheels will work. It doesn't seem like there's any obvious place for it to go without creating a ton of drag. EDIT: I guess the autotopia was ahead of its time. Also, I want to try to do some estimation of the capacity of this system compared to subways sometime soon.

Webcast is up, this is the direct link: https://www.ustream.tv/channel/nPnTNTAvu2E

As far as I can tell, they are essentially considered the same "prime ideal" in advanced math, and so basically ignored. The standard definition of a prime is a natural number greater than 1. https://primes.utm.edu/notes/faq/negative_primes.html https://math.stackexchange.com/questions/1002459/do-we-have-negative-prime-numbers

The only exception would be if the negation of each prime was considered prime as well, in which case it would converge to 0. However, they aren't included in the definition of primes.

701 The biggest gap in the primes under 10000 is 36, between 9551 and 9587.

https://twitter.com/elonmusk/status/1075152373880782848

The F-104 could reach mach 2 though, right?

rot_matrix = np.array([xorientation, yorientation, zorientation])

You forgot the part where you burn the wood in trains that drive in circles for no purpose but to use up your massive backlog of wood. I've always preferred flamethrower then shotgun to remove the trees before bots.

I'll see your time lord and raise you a mathematician:

Landing tube for BFR? Probably not, I would guess the infrasound would be too much.

Thanks, these posts are really helpful.

I've been keeping an eye on this game, it looks good. I like factorio, so I expect I'll like this game too.

Epic games is doing a thing where the have a free game every two weeks to promote their store. The next one is Super Meat Boy, which I think has lower requirements.

I wonder whether a magnetic field drive would be more efficient than a photon drive. Photon drives set the gold standard for energy inefficiency, so I suspect it would be better.

Alright, so school is over and I have some more time to work on this again. Currently I'm using this code for the position (velocity verlet): rocket.position += rocket.velocity * dt + 0.5 * rocket.acceleration * dt * dt But then I'm using forward Euler for velocity: rocket.velocity += rocket.acceleration * dt This PDF on slide 53 shows another way of calculating velocity. Should I try to use that (I'm not sure how to compute Ft + dt from positiont + dt and velocityt + dt, I'm currently calculation force as the sum of thrusts divided by mass) or is Euler close enough? The slide uses h where I'd use dt, X where I'd use position, and V where I'd use velocity, FYI. And I'm afraid I'm going to have to cry uncle on trying to figure out Verlet for rotation. Does anyone have any sources for what Euler would look like for rotation? I think I understand most of it (torque ~ acceleration, angular momentum ~ velocity, and the three unit orientation vectors which make up the rotation matrix ~ position), however the way torque affects, say, a tube is different dependent on what direction it is applied in. I think that difference can be modeled with the moment of inertia tensor, but I'm not sure how to make that, or what it would even look like. Would it be a three dimensional array in 3D?

rocket.velocity += rocket.acceleration * dt

Subnautica, picked it up since it was free on the Epic games store. It's free from now till December 27th, I'd recommend it even if you don't normally like survival games.

All these westerns are reminding me of this:

If you're having trouble with biters, have you tried setting up piercing ammo production? They are more powerful than they look based just on damage because of the way armor works in the game. It's also super easy to just feed it right into your existing turret belts.

I agree, the expansion ratio looks too large relative to the nozzle length to me. https://www.spacex.com/sites/all/themes/spacex2012/images/reveal-merlin-inner.png