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.
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?
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..?