Quiz question...

[imamartian]

This is trivial.
Radius is R
CIrcumference C is 2 x pi x R
SO the difference in C is 2 x pi x 2 feet
which is near enough a couple of metres.
Or 6.28 feet.

---
Can I ask one??

The acceleration of an astronaut in a Saturn 5 (moonmission) rocket is about 3g. They reckoned that's about all one could stand, for the period.
So, ignoring relativistic effects (for now) how long would it take him to get to half the speed of light?

I can do it in my head and I'm only a plumber, so you should be able to too. (hint, take g as 10 m/s/s)


Or, if arethmatriculation isn't your thing, but keeping it astral, what's earth's nearest star?

Surely 3g is a state? (not a mobile phone network !!),,, but speed would be 3g per second, and an acceleration would be 3g per second per second?

 

[ChrisR]

Yes it's the sun , then I believe Proxima Centauri.



g is the acceleration due to gravity, measured in metres per second per second.
Speed in the same system is metres per second
so if the speed of light is 3e8 metres per second, and you accelerate at 10 metres per second, per second..., how long...

( 3e8 being notation for 3 followed by 8 zeroes)

 

[Space cat]

In theory, at a constant acceleration of 30 m/s/s, you would reach 150,000,000 m/s in 5,000,000 seconds. Sadly, your fuel supply would not last that long.

 

[imamartian]

another question for people to mull over.....

why do planes always have 2 contrails regardless of whether they have 2 or 4 engines?

(if you know, then say so, but don't give it away until other bods have guessed..)

 

[oompah]

I don't know but I won't tell

 

[wotan]

Me neither

 

[oompah]

Picture clue.
View media item 26117

 

[Space cat]

Edit: Oops! I've just read the post properly.

Answer deleted.

 

[imamartian]

Picture clue.
View media item 26117

err.. apart from in this scenario !!

 

[Karinska]

Is it because you're flying Ryanair so only 2 of the 4 engines work

 

[imamartian]

Is it because you're flying Ryanair so only 2 of the 4 engines work

ha ha... useful for those on here who are afraid of flying !!

 

[Space cat]

Here's a clue. What do most planes have two of?

 

[oompah]

What do most planes have two of?

Chances they either fly or they don't.

 

[ChrisR]

5,000,000 seconds

ABout a coupleof months. Fuel might last, but humans couldn't stand that acceleration for that long.
So if we're ever going to go far in the universe, which means travelling at that sort of speed, we're going to have to face it taking a year or more to get up to speed.

 

[ChrisR]

why do planes always have 2 contrails regardless of whether they have 2 or 4 engines

DUnno.
Is it because each wingtip vortice promotes condensation from supersaturated atmosphere?