A Jet Plane in Straight Horizontal Flight Passes Over Your $\degree$

question 46

Multiple Choice

A jet plane in straight horizontal flight passes over your head.When it is directly above you, the sound seems to come from a point behind the plane in a direction 30 $\degree$ from the vertical.The speed of the plane is:

• A)the same as the speed of sound
• B)half the speed of sound
• C)three-fifths the speed of sound
• D)0.866 times the speed of sound
• E)twice the speed of sound