Based on the rate the bird is flying and the distance above your head, the speed of change in the angle of elevation is 0.018 rad/sec.
First use the Pythogoreous theorem to find the distance between you and the bird at 80 m:
= √(60² + 80²)
= √(3,600 + 6,400
= 100 m
Cos² = 80² / 100²
= 16 /25
Differentiate this to get:
= ((-60 x 16/25) / 80²) x (-3)
= 9/500
= 0.018 rad/sec
Find out more on angle of elevation at https://brainly.com/question/2004882.
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