Two point sources, S1 and S2, oscillating in phase send waves into the air at the same wavelength, 1.98m. Given that there is a nodal point where the two waves overlap, find the smallest corresponding path length difference.

Most energy in an ecosystem comes originally from_

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=

How many astronauts have walked on the moon?