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@MOTIVELC
KEY
13. i
14. iii
15. v
16. vii
17. ix
18. x
19. TRUE
20. NOT GIVEN
21. FALSE
22. TRUE
23. NOT GIVEN
24. NOT GIVEN
25. FALSE
26. TRUE
27. excellence, respect, friendship
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@MOTIVELC
Hurricane
They are essential features of the Earth’s atmosphere, as they transfer heat and
energy between the equator and the cooler regions towards to poles.
Section A
A hurricane is a large rotating storm centered around an area of very low
pressure with strong winds blowing at an average speed in excess of 74 miles per
hour. The whole storm system may be up to 10 miles high and on average 500 miles
wide. It moves forward like an immense spinning top, at speeds up to 20 mph.
Section B
There are various trigger mechanisms required to transform frequent storms
into rarer hurricanes. These trigger mechanisms depend on several conditions being
‘right’ at the same time. One of the most influential factors are sources of very warm,
moist air, which derived from tropical oceans with surface temperatures greater than
26°C, and sufficient spin or twist from the rotating earth, which is related to latitude.
As the warm sea heats the air above it, a current of very warm moist sir rises
up quickly, creating a center of low pressure at the surface. Trade winds rush in
towards this low pressure and the inward spiralling winds whirl upwards releasing
heat and moisture before descending.
The rotation of the Earth causes the rising column to twist, gradually taking on
the form of a cylinder whirling around an eye of relatively still air, free from clouds.
The rising air cools and produces towering cumulus and cumulonimbus clouds.
Further aloft at 6 miles the cloud tops are carried outwards to give thick layer clouds
due to the outward spiraling winds leaving the hurricane core.
Section C
Great amounts of energy are transferred when warm water is evaporated from
tropical seas. This energy is stored within the water vapor contained in moist air. As
this air ascends, 90% of the stored energy is released by condensation, giving rise to
the towering cumulus clouds and rain.
The release of heat energy warms the air locally causing a further decrease in
pressure aloft. Consequently, air rises faster to fill this area of low pressure, and more
warm moist air is drawn off the sea feeding further energy to the system. Thus a self-
sustaining heat engine is created.