Suppose the electric field in some region is found to be e = kr3 ˆr, in spherical coordinates (k is some constant). (a) find the charge density rho. (b) find the total charge contained in a sphere of radius r, centered at the origin. (do it two different ways.)

Answerstatic electricity shock;

Ithink it's  c. i'm sure 

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.

The correct option is this: the sound waves from the two trombones have slightly different frequencies.from the question given above, we are told that the loudness of the sounds were increasing and decreasing, this is because the frequencies of the two sounds are different. the means that the number of waves that pass a fixed point in a given amount of time differ for both sounds.