Qualification > Sciences
Edexcel PHYSICS Doubts
The Golden Girl =D:
Omega (Angular velocity) = 2 pie / T
T = 600 revolutions per minute.
Omega at the end is supposed to be about 63 rads-1
I know this is Math , but I just can't seem to get the answer =,=
Thanks =]
Banana:
--- Quote from: ~The Golden Girl~ on October 01, 2011, 09:24:26 am ---Omega (Angular velocity) = 2 pie / T
T = 600 revolutions per minute.
Omega at the end is supposed to be about 63 rads-1
I know this is Math , but I just can't seem to get the answer =,=
Thanks =]
--- End quote ---
w = 2pi / T
T is the period (time taken for one rotation) SO for 600 rpm each rotation takes 60/600 seconds = 0.1 sec
Substitute into the equation:
w= 2pi / (0.10) = 63 rad s-1 as the question says ;)
The Golden Girl =D:
--- Quote from: ~Mujta-BaM! on October 01, 2011, 09:38:52 am ---w = 2pi / T
T is the period (rotations in one second) SO for 600 rpm there will be 600/60 revolitions per second( the period)
Substitute into the equation:
w= 2pi / (10) = 0.63 rad s-1
So basically it isn't 63 but 0.63 ;)
--- End quote ---
In the Question it says it's about 63 though. and isn't 600 supposed to be multiplied by 60 ? :-\
Another Question ,
Q. The average wind speed in the UK is 5.8 m s–1, which results in an actual average power output of 100W. Discuss whether it would be better for the environment to replace some filament light bulbs with low energy bulbs than to use this turbine. Assume each filament light bulb is rated at 100W and each low energy bulb is rated at 11 W.
Answer. The 100 W is an average over the whole day. Most households would use light bulbs for 6 hours a day in no more than 4 rooms, so this would mean no other energy was needed for lighting. 4 low energy bulbs would be 44 W for 6 each hours so would require energy from the National grid.
I don't get it.
Thanks =]
The Golden Girl =D:
--- Quote from: ~Mujta-BaM! on October 01, 2011, 09:38:52 am ---w = 2pi / T
T is the period (time taken for one rotation) SO for 600 rpm each rotation takes 60/600 seconds = 0.1 sec
Substitute into the equation:
w= 2pi / (0.10) = 63 rad s-1 as the question says ;)
--- End quote ---
Today my brain is BLANK ::) so hmm why did you divide 60 by 600 ?
Explain it in details please :-[ :-\
Banana:
--- Quote from: ~The Golden Girl~ on October 01, 2011, 11:36:35 am ---Today my brain is BLANK ::) so hmm why did you divide 60 by 600 ?
Explain it in details please :-[ :-\
--- End quote ---
Okies....
Period is the time taken for one rotation..
Using proportion:
Revolutions Time
600-------------------> 1 minute =60 seconds
1 --------------------> T seconds
Cross multiply: 600T = 60
Therefore, T = 60/600 = 0.1 seconds
This is the period!
All you have to do now is substitute into the equation: w= 2pi/ T
Voila!! 8)
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