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A bird is sitting on the top of a 60 m high tree. From a point on the ground, the angle ofelevation of the bird is 60 degree. The bird flies away horizontally in such a way that itremained at a constant height from the ground. After 2 seconds, the angle of elevation ofthe bird from the same point is 30 degree. Find the speed of the flying bird. |
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Answer» Answer: 20√3 m/s Step-by-step EXPLANATION: tana=p/b p=height of tree=60m tan60°=60/b √3=60/b b=60/√3 b=60*√3 / √3*√3 b=60√3 / 3 b=20√3 tanb=p/b tan30°=60/b 1/√3 = 60/b b=60√3m distance travelled=60√3 - 20√3 =√3(60-20) =40√3m speed =distance/time =40√3/2 = 20√3 m/s |
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