Click Play, and then click Pause just after the plane has passed the observer. What is the frequency of sound waves behind the plane?

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

Iwould say the answer is b.  christians believed jesus was the messiah, or savior of man.  because most jews do not believe  in jesus

Thick and thin filaments

I’m not sure about this question