8. What is the frequency heard by a person driving at 15.0 m/s toward a blowing factory whistle (800. Hz) if the speed of sound is 340.6 m/s? (837 Hz) F= (340.6×800)÷(340.6-15)= 836.9 Hz F=836.9 9. From the previous problem, what frequency would he hear after passing the factory if he continues at the same speed? (766 Hz)

Point charges q1=+2.00μc and q2=−2.00μc are placed at adjacent corners of a square for which the length of each side is 1.50 cm . point a is at the center of the square, and point b is at the empty corner closest to q2. take the electric potential to be zero at a distance far from both charges. part a what is the electric potential at point a due to q1 and q2? express your answer with the appropriate units.