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Grade 10Mechanics

A plane is revolving around the earth with a speed of 100km/hr at a constant height from the surface of earth. The change n velocity after completing ½ revolution will be?
a) 200km/hr
b) 150km/hr
c)300km/hr
4) 400km/hr

Profile image of jothilakshmi
7 Years agoGrade 10
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1 Answer

Profile image of Arun
7 Years ago
when the aeroplane revolving around the earth, velocity vector changes 180º when it completes half circle.
Hence if initial velocity is v, after completing half circle, velocty becomes -v. Hence change in velocity v - (-v) = 2v. 
In the given question v = 100 km/hr. hence change in velocity is 200 km/hr