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anonymous
 one year ago
An aeroplane travels at an average speed of 600kmh1 on an outward flight and at 400kmh1 on the return flight over the same distance
What is the average speed of the whole flight? A) 111ms1 B) 167ms1 C)480kmh1 D)500kmh1
anonymous
 one year ago
An aeroplane travels at an average speed of 600kmh1 on an outward flight and at 400kmh1 on the return flight over the same distance What is the average speed of the whole flight? A) 111ms1 B) 167ms1 C)480kmh1 D)500kmh1

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I know a blog for physics mcq"s you're doing alevel?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Some may give the average as (600 + 400) / 2 = 500 km h1. [Choice D] But this is wrong. Averages are not that simple unless the 2 times are the same and not the 2 distances. Average speed = Total distance / Total time Let distance travelled for outward flight, which is equal to the distance travelled for inward flight = d. So, total distance travelled for the outward and return flights = 2d. For each flight speed, v = d / (time, t). The time will be different since the speed is different for the flights. let time for outward flight = tout. tout = (d/600) h. [h: hour] let time for inward flight = tin. tin = (d/400) h. Total time, t = tout + tin = d/600 + d/400 = (d/240) h Average speed = total distance / total time = 2d / (d/240) = 480 km h1

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0^ this solution is copied its from http://physicsref.blogspot.com a really great blog for physics alevel.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Oh thankyou so much :') And yes i am doing alevels
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