Author Question: A siren emitting sound of frequency 1000 Hz approaches a stationary observer at one-half the speed ... (Read 116 times)

charchew · **on:** Jul 29, 2018

A siren emitting sound of frequency 1000 Hz approaches a stationary observer at one-half the speed of sound. The observer hears a frequency of

A) 1000 Hz
B) 2000 Hz.
C) 500 Hz.
D) 1500 Hz.
E) none of the above.

Question 2

A particle of charge +2q is placed at the origin and particle of charge -q is placed on the x-axis at x = 2a. Where on the x-axis can a third positive charge be placed so that the net electric force exerted on it is zero?

A) 3.4a
B) 6.8a
C) 8.6a
D) 9.3a
E) 1.0a