Trigonometryhard · Past Paper
A bird is sitting on top of an 80 m high tree. From a point on ground, elevation is 45°. Bird flies away horizontally. After 2 seconds, elevation is 30°. Find speed of bird.
A40(√3-1) m/s
B40√3 m/s
C20√3 m/s
D80 m/s
✓ Correct Answer: A — 40(√3-1) m/s
Initial distance d1 = 80/tan 45 = 80. Final distance d2 = 80/tan 30 = 80√3. Distance traveled = 80(√3-1). Speed = 80(√3-1)/2 = 40(√3-1) m/s.
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