SolderIron
Addicted Member
You don't need stinking math. Go get a couple rolls of twine, tie a weight to the end and unroll it down the hole 
Physics Problem
- Thread starter toxcrusadr
- Start date
drknstrmyknight
Addicted Member
That of course was when a vacuum enveloped the tower, way back when.
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F),
(From WIKIPEDIA)
That is at sea level. How high is the opening of the mine shaft above sea level, what is the temperature of the air in the shaft? What is the humidity?
This is getting way too complicated isn't it?
I'm with SolderIron.
(From WIKIPEDIA)
That is at sea level. How high is the opening of the mine shaft above sea level, what is the temperature of the air in the shaft? What is the humidity?
This is getting way too complicated isn't it?
I'm with SolderIron.
FreeOrange
Well-Known Member
Maybe we just ask the goat.
Okay, so why all this crazy math, then?
10.442 * 9.8m/s = 102.3316 m/s (velocity at bottom, terminal velocity has got to be higher than that).
102.3316m/s / 2 = 51.1658 m/s (average speed)
51.1658m * 10.442 = 534.27m deep = 1752.8'.
right? :scratch2:
OK. I think I have just lost too much of the math to follow this so I should just take your word for it. I think I lost you at the three equations that somehow lead to that long quadratic where everything equals zero. :scratch2:
Anyway, cool that there is someone here smart enough to solve that!
I would like to see the drill that bored that hole, must be 5 ft. in diameter...
Har! The miners already ate him.
usedto
Lunatic Member
You ought to see the outhouse that goes on top. And it wasn't a rock.
Post Of The Thread! :lmao::lmao:
Yeesh, someone needs to eat more fiber then.
Welcome to the Genius Idjits Club! :thmbsp:
I got ya beat. I solved the thing in two seconds. Then I realized I only read half the problem.
Luckily, I deleted my post before anybody saw it. :stupid:
aabottom
Swing
So, I guess that you realized that you need "all this crazy math" to get to the rock fall time of tf = 10.422 seconds. And yes, your right, this is the "drag free" solution which gives a final velocity of 229 MPH. This is likely much higher than terminal velocity (nominally 120 MPH). The air resistance drag solution is more complicated and we were not given the size or drag coefficient of the rock.
In the real world, the hole would be shorter than 1754 feet.
Actually, this is high school freshman math. Any college-bound 9th or 10th grader (even a smart 8th grader) should be able to solve it. One of the most important things that one should learn in high school is how to derive the solution of the quadratic equation.
120 mph is the rule-of-thumb for a spread-eagled skydiver, not a rock... Could drag really cause much error here? Less than errors on the actual speed of sound, I would guess.
Yes, I remember doing that as a smart 8th grader. Guess I got my comeuppance today. You know what they say, use it or lose it. I do take comfort in the fact that I have learned one or two other things since then, and gained at least a thimbleful of wisdom as well, so I am hopefully not a completely useless member of society despite being unable to do math I haven't used for 30 years.
Oops, look at the time! Gotta go clean up a few hazardous waste sites. :thmbsp:
usedto
Lunatic Member
That way you can accurately predict how many burgers you can flip in one hour.:thmbsp:
Brian
An Old Geezer
I thought the most important thing to learn in high school was why there are separate phys ed classes. One of the best lessons I learned was the use of the photo dark room for purposes other than developing film. Found out other things could develop there.
Seriously, the lesson to learn there is time management and study skills. If you do not learn it by graduation, then neither undergrad school or a job is too late without a severe cost.
Seriously, the lesson to learn there is time management and study skills. If you do not learn it by graduation, then neither undergrad school or a job is too late without a severe cost.
whoaru99
Epic Member
Dunno where you went to high school, and it's been quite a few years for me, but I don't recall seeing anything like this in 8th, 9th, or 10th grade. Maybe there was and I just don't remember it that way.
x = vs*[(vs+v0)/a0+t-sqrt{[(vs+v0)/a0+t]^2-2*(x0+v0*t)/a0-t^2}]