1
Just Chat! / Re: Freudian Word Link
« on: 18/04/2011 17:39:34 »
Emo
(Have a friend called hannibal who's an emo! [
])
(Have a friend called hannibal who's an emo! [
])
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3
Chemistry / Test for Barium Hydroxide?
« on: 18/04/2011 11:37:04 »
Also.. The manufacture and use of 1,1,1-trichloroethane is now restricted because of its adverse effects on the ozone layer. However, the corresponding fluoro-compound 1,1,1-trifluoroethane does not cause environmental problems in the ozone layer. Explain why only the chloro-compound has these adverse effects.
4
Physics, Astronomy & Cosmology / A Bungee Jump Question!
« on: 18/04/2011 11:17:34 »
Wow - thanks for the answers.. Just a bit of physics past papers, but having no mark scheme doesn't help much!
Must say, the first two replies were a little beyond me [
]
Must say, the first two replies were a little beyond me [
]
5
Chemistry / Test for Barium Hydroxide?
« on: 18/04/2011 11:13:53 »
Here is the question..
A solution, giving an apple-green colour to a flame, was suspected to be aqueous barium hydroxide.
Describe two simple tests to confirm this conclusion, giving the result of each test.
Now, I've only been taught that to test for Barium ions you do a flame test, which gives an apple-green colour!
Do I do litmus to test for alkalinity?
A solution, giving an apple-green colour to a flame, was suspected to be aqueous barium hydroxide.
Describe two simple tests to confirm this conclusion, giving the result of each test.
Now, I've only been taught that to test for Barium ions you do a flame test, which gives an apple-green colour!
Do I do litmus to test for alkalinity?
7
Physics, Astronomy & Cosmology / A Bungee Jump Question!
« on: 15/04/2011 10:05:48 »
Thanks for the help everyone [
]
A 'bungee jumper' standing on a high platform above the ground is attached to a bungee cord of unstretched length 26m and spring constant k. When she jumps she falls a maximum distance of 96m where she is momentarily stationary at the lowest point of her jump and begin moving upwards. Ignore air resistance.
Then there's a graph of Tension against Extension.
i) Using the graph, calculate the elastic potential energy stored in the bungee cord when the jumper is at the lowest point.
Is that by working out the area under the graph? Which I got to be 56,000J
ii) Initial gravitational potential energy (with respect to ground) possessed by the jumper on the platform is 7.0 x 10^4J and her mass is 60kg. Calculate how high she is above the ground at the bottom of her fall.
Here, I did mgh = 7.0x10^4 and got h = 118.9. I then took away 70m as that was the highest extension as shown on the graph.
iii) After bouncing a few times, the bungee jumper eventually comes to rest hanging a distance, d, below the platform
Now I'm shtuck [] Have I got all the bits before right?
]A 'bungee jumper' standing on a high platform above the ground is attached to a bungee cord of unstretched length 26m and spring constant k. When she jumps she falls a maximum distance of 96m where she is momentarily stationary at the lowest point of her jump and begin moving upwards. Ignore air resistance.
Then there's a graph of Tension against Extension.
i) Using the graph, calculate the elastic potential energy stored in the bungee cord when the jumper is at the lowest point.
Is that by working out the area under the graph? Which I got to be 56,000J
ii) Initial gravitational potential energy (with respect to ground) possessed by the jumper on the platform is 7.0 x 10^4J and her mass is 60kg. Calculate how high she is above the ground at the bottom of her fall.
Here, I did mgh = 7.0x10^4 and got h = 118.9. I then took away 70m as that was the highest extension as shown on the graph.
iii) After bouncing a few times, the bungee jumper eventually comes to rest hanging a distance, d, below the platform
Now I'm shtuck [
] Have I got all the bits before right?
8
Physics, Astronomy & Cosmology / A Physics Question..
« on: 15/04/2011 09:53:29 »
Bugger [] I meant that he drops it outside the window
] I meant that he drops it outside the window
9
Physics, Astronomy & Cosmology / A Physics Question..
« on: 15/04/2011 09:44:00 »
Thanks. And if it were to have air resistance. It would appear from the passenger's point of view to be going backwards.
But from an observers point of view, it would go in the direction of the train, but with a smaller velocity?
But from an observers point of view, it would go in the direction of the train, but with a smaller velocity?
11
Physics, Astronomy & Cosmology / A Physics Question..
« on: 15/04/2011 09:23:43 »
If you have a passenger inside a train, and he drops a ball.. If you neglect air resistance, would the ball be horizontally motionless to the passenger?
12
Physics, Astronomy & Cosmology / Why is high-pitch noise harder to distinguish where it's coming from?
« on: 04/04/2011 12:08:44 »
There was a really annoying high-pitched noise coming from our house, and I could not find where it was coming from! Now, if it was a low-pitch noise, like a low humming, it is so easy to find its origin. But what makes it different for a high-pitch noise?
Its high frequency and short wavelength? Even so..?
Its high frequency and short wavelength? Even so..?
13
Just Chat! / Tell us about your 2011 Valentines date or celebration?
« on: 16/02/2011 23:21:21 »
Me and Neil had a nice long chat through facebook messages! Sorry to ruin your birthday like that! [
]
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14
Just Chat! / Household Animal Look-a-like of the day !!
« on: 15/02/2011 21:51:49 »
I'm not sure about you..
But doesn't my lamp look a bit like a duck??
Maybe it's just me...
But doesn't my lamp look a bit like a duck??
Maybe it's just me...
16
Just Chat! / Forum Game 5 letter words- Change one Letter!
« on: 15/02/2011 14:18:42 »
Faster
Hey demografx! It was only rude if you wanted it to be! Gwrr []
Hey demografx! It was only rude if you wanted it to be! Gwrr [
]
17
Just Chat! / Tell us about your 2011 Valentines date or celebration?
« on: 15/02/2011 14:16:33 »
Pretty much the same as yours! []
]
18
Just Chat! / HAPPY BIRTHDAY NEIL! (aka Sheepy)
« on: 15/02/2011 11:12:32 »
DARE DEVIL SHEEEEEEEP!
Happy Birthday! X
Happy Birthday! X
19
Just Chat! / Forum Game 5 letter words- Change one Letter!
« on: 13/02/2011 13:04:36 »
Harder.
How rude of you demografx! There are kids on this forum too! []
How rude of you demografx! There are kids on this forum too! [
]