theydidthemath

[Request] How fast would a rollercoaster have to be going to do this?

[Request] How fast would a rollercoaster have to be going to do this?
There's no parabolic path to match a velocity to, it's just a straight line. So the closest answer you're going to get is "fast enough that that it appears to follow a straight path for the distance that it's in the frame of this picture." From the photo I'd say it'd have to go about 300mph to not notice the ballistic trajectory. But again, there can be no definitive answer to this.

Edit: To give everyone a better idea, I plugged in some numbers and graphed the resulting trajectories for a launch angle of 30 degrees and speeds of 150mph (about 70 m/s) and 300mph (about 140 m/s), respectively. Both the x and y axes are in meters.

150mph

300mph

Notice how at 150mph you can clearly see the curved trajectory, and at 300mph you cannot easily see it.

There's no parabolic path to match a velocity to, it's just a straight line. So the closest answer you're going to get is "fast enough that that it appears to follow a straight path for the distance that it's in the frame of this picture." From the photo I'd say it'd have to go about 300mph to not notice the ballistic trajectory. But again, there can be no definitive answer to this.

Edit: To give everyone a better idea, I plugged in some numbers and graphed the resulting trajectories for a launch angle of 30 degrees and speeds of 150mph (about 70 m/s) and 300mph (about 140 m/s), respectively. Both the x and y axes are in meters.

300mph

Notice how at 150mph you can clearly see the curved trajectory, and at 300mph you cannot easily see it.

I'm fairly certain the answer is a million jillion miles per hour. Source: have a kid.

But roller coasters don't just float off the track. We'd also need to know how much force it would take to break off the wheels that run on the bottom of the track.

Not just break off the wheels but to snap them off so abruptly that there is no noticeable jolt or velocity decrease

[Request] Which side has greater military power?

[Request] Which side has greater military power?

In an all-out shooting war between these rosters, everyone loses in a global nuclear holocaust, obviously. But if we're just sizing things up, we can look at this list of the world's militaries by personnel

The left column here (including the U.S.) totals up to 3.495 million active personnel. The right column totals up to 3.826 million active personnel. Advantage Team "Don't Bomb Syria."

Of course, even if we're assuming this war wouldn't be fought with nukes, it probably wouldn't be fought with fisticuffs either. And given modern warfare technology, military budget is probably a better metric of strength. So, let's use this list which shows the military budget of every country.

By this metric, the left column (again, including the U.S.) totals up to 986.4 billion USD (with the U.S. making up almost two thirds of that). The right column totals up to 301.2 billion USD. MASSIVE advantage Team "Bomb Syria."

TL;DR - The two sides are pretty evenly matched in terms of raw military size, but the guys on the left outspend the guys on the right 3:1.

I wonder if comparing military budgets in this way is fair though. Sure, Russian military budget is much smaller when expressed in USD, but local resources & labor are also much cheaper in Russia. About the same goes for China, I suppose.

I agree. Also, if a world war kicked off, then all countries' military budgets would no doubt increase. Then it becomes a question of who can distribute more GDP % towards military.

Considering the countries, the group on the left would still overwhelm, if not even more so, the right group.

[Request] How much would this actually cost in comparison to just building the wall separating Mexico from the U.S.?

[Request] How much would this actually cost in comparison to just building the wall separating Mexico from the U.S.?

Now with formatting!

US Mexico border = 1,951 miles

New Mexico border = 1,434 miles

New Mexico Mexico border = 180 miles

As shown the wall would be 3,025 miles, approximately 55% longer.

US Mexico border = 1,951 miles https://www.google.com/?gws_rd=ssl#q=length+of+us+mexico+border New Mexico border = 1,434 miles http://www.city-data.com/states/New-Mexico-Location-size-and-extent.html New Mexico Mexico border = 180 miles http://www.usborderpatrol.com/Border_Patrol746.htm

As shown the wall would be 3,025 miles, approximately 55% longer.

When I saw this post, I thought "there's no way he said something that stupid". And for once, I was actually right.

According to THIS source, the wall as currently planned would cost anywhere from $10 billion to $25 billion, so let's settle in the middle and say $17.5 billion.

55% of $17.5 billion is $9.63 billion.

$17.5 billion + $9.63 billion = $27.13 billion

And that's the average, remember. If it was the high end, you'd be looking at like $39 billion.

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[Off-Site] My uncle (who has MS and cannot write) created an algorithm to replicate his old handwriting through a plotter. https://m.youtube.com/watch?v=W5YGwNlO53A

[Off-Site] My uncle (who has MS and cannot write) created an algorithm to replicate his old handwriting through a plotter. https://m.youtube.com/watch?v=W5YGwNlO53A

I just saw his post on /sub/python! Really amazing!

Your uncle is a rockstar.

Could you ask him if next he could design a robotic hand that gestures in response to vocal cues?

"T-T-T-T" makes the fingers drum in impatience, "shhh" is a comforting pat, a sharp "Fsss!" flips you the bird...

I have an Italian friend with MS and she really misses "talking with her hands."

Actually, it wouldn't even have to be a 3D hand, it could just be a 2D screen display/animation.

"It may not be the most readable"

>written in flawless cursive.

Link to said post: https://www.reddit.com/sub/Python/comments/62q2sm/python_helped_me_write_again/

[Request] How far away is Saturn in the bottom frame?

[Request] How far away is Saturn in the bottom frame?

Saturn's rings at the front are about as wide as the heads of the people in the foreground.

If we assume that they are 1m away from the viewer:

Size_rings/Size_head = Distance_rings/Distance_head

Heads are about 30cm tall, Saturn's rings are about 73,000km wide.

Distance_rings = 73,000km/30cm * 1m Distance_rings = 243,333km

It's about 140,000km from the edge of Saturn's ring's to it's centre

So about 384,000km away - basically where the Moon is (average orbital radius 385,000km).

EDIT (EDITED):

As people have pointed out, the rings are tilted and I didn't factor in that this would make them appear thinner from the panel POV.

So to fix this I am going to re-run the maths with a different point of reference - the planet itself!

I checked 3 points on the edge of the planet and worked out that the circle that goes through all of them has a radius of 94.5 mm. The screaming heads in the foreground have a height of 36 mm. We'll assume the same height of head: approx 30cm, so a mm in the image is about 1.20.83cm. This means that Saturn's apparent radius is 1.1340.7875m.

Radius_Saturn/Apparent_Radius_Saturn = Distance_Saturn/Distance_reference 58,232 km / 1.1340.7875m = Distance_Saturn / 1m Distance_Saturn = 51,35173,945 km

Which would be very bad.

This might vary a lot depending on how far you think it actually is to the screaming man in the lower right, if it's further than 1m, Saturn would be correspondingly further away.

Sorry for the mistake - I added the second calc just before bed and missed the fuckup

Nice

You fucked it up.

I often look at the moon and am amazed at how far away it actually is, and how large it must be, from such a distance. Your calculations, assuming they're correct, really puts into perspective how large Saturn actually is...

[Self] It's more water efficient to pee in the shower as long as you spend less than 38 seconds to pee

[Self] It's more water efficient to pee in the shower as long as you spend less than 38 seconds to pee

Doesn't this assume that you don't do anything other than peeing in that time?

For example, if you pee'd while you put shampoo in your hair, the "water saved" would stay static

Yes it does. It's more generous than I had previously thought though before I wrote it out. I'd say a solid morning pee is about 20 seconds long. The 38 second point means that you'll basically always be saving water by peeing in the shower even if you don't want to shower.

Wow, "a solid morning pee" for 20 seconds must hurt like hell

I've literally pissed for about a minute in the morning before. Sometimes, it just never ends

[request] Are there more blades of grass or stands of hair on Earth?

[request] Are there more blades of grass or stands of hair on Earth?

Strands of hair would include insect hairs, but not things like flagellum.

100,000,000,000 blades of grass p sq km, if we assume every sq km of land 148,300,000 sq km has grass at this density(it doesn't, just roll with me for a second) we get 1.48300e19 blades of grass, but again this far exceeds the actual amount of grass on earth.

There are around 5,000,000 hair follicles on a human, multiply by 7,000,000,000 for 3.5e16 hairs for the human race. I don't think it's much of a stretch from there to assume that combined with all other haired creatures on earth the number of hairs vastly exceeds even our outrageous grass count.

Obviously there's a lot of assumptions and averaging here but I think it puts the question into perspective enough to arrive at a pretty solid conclusion.

edit: missed a decimal

[Request] If the wall were built to Trump's specifications, what would be the area of the rectangular pieces?

[Request] If the wall were built to Trump's specifications, what would be the area of the rectangular pieces?

Wikipedia gives the length of the border as 3201 kilometers. 3201 divided by 471612 rectangles gives a length of a about 6.78 meters to each tile. I'm going to assume that the little cartoon man is about 1.8 meters tall (roughly 6 feet), and I'm going to assume the rectangle is 3 times as tall as he is. That gives each tile dimensions of 5.4 by 6.78 meters, or ~18 feet by ~22 feet. This gives one tile an area of 36.6 meters squared. Thus, 471612 tiles is a total area of 17266658.54 meters squared, or ~20650751 yards squared. I have read that Trump wants a 40-ft high wall, but given that my dimensions already seem off to what the cartoon shows, I think that over 470000 40-ft tall tiles would be excessive to say the least.

[Self] 50 Shades of Shit

[Self] 50 Shades of Shit

Correction, millions of women is still a fuckton of women.

Try one of these subthreads