Water is made to fall drop by drop on the surface of a pool at the rate 120 drops per minute. As a result, circular ripples are formed on the surface and the distance between the third circle and the seventh circle is 60m. a) Calculate the frequency, period and wavelength.
b) Deduce the speed of propagation of the waves on the water surface.

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.

19 hertz bruh u trippin? ?