Monday, September 12, 2011

Power questions

PFY, p. 120
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f) power is the rate of doing work.
   power (in watts) = work done ( in joules) / time (in seconds)
g) 1 watt is a rate of working of one power joule per second.

13. P=E/t    1000/5= 200watts 

14. P= E/t     (300 x 2) / 6= 100watts

16. P= E/t       (3000 x 10) / 4 = a) 7500watts
                                                       b) 7.5 kilowatts

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