Since work is the change in kinetic energy, the efficiency of a machine can be stated as the percentage of the output work divided by the input work minus the work lost from to friction and heat. Multiply Eff by 100% to get the efficiency percentage.
<em>The answer is </em>Ninth <em>and </em>Tenth <em>grade so the answer would be</em> B
<em>I hope this helps you </em>
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Explanation:
Answer:
c
Explanation:
efficiency is measured in % hence 0.02% is smaller than 20%
(2.00 hours) x (3,600 seconds/hour) = 7,200 seconds
(9.00 minutes) x (60 seconds/minute) = 540 seconds
The record time = (7,200 + 540 + 21) = 7,761 seconds
Distance = (speed) x (time)
= (5.436 m/s) x (7,761 sec) =<span> 42,188.8 meters
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The official length of the marathon run is 42,195 meters.
If we divide that by the record time in the question, we get
5.4368... m/s .
Rounded to the nearest thousandth, that's 5.437 m/s.
If the question had given the speed as 5.437 instead of 5.436 ,
then we would have calculated the distance to be
(5.437 m/s) x (7,761 sec) =<span> 42,196.6 meters,
4.6 meters closer to the official distance than the answer we did get.
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