1. A jet plane in straight horizontal flight passes over your head. When the plane is directly above you, the sound seems to come from a point behind the plane in a direction 45° from the vertical. The speed of the sound is vs. The speed of the plane is about:
(A) vs
(B) 0.5vj
(C) 0.7 Ivj
(D) 1.41vj
(E) 2vs.
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統計: A(0), B(0), C(0), D(1), E(0) #3221220
統計: A(0), B(0), C(0), D(1), E(0) #3221220
詳解 (共 2 筆)
#7402657
所以聲音走的路線是斜線的
飛機走的路線是水平的
所以如果你在考試中遇到飛機在你上方
聲音從後方cita傳過來
可以套用飛機速度會等於聲音速度乘以sincita
所以直接把vs乘以sin45度即為所求
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