John and Tou take their toys down to a nearby pond to play. John has a toy boat made from wood. He places the wooden boat on the pond and it floats. Tau, being a checky little boy, wants to make John's
wooden boat sink. So he attaches a piece of lead on one end of the string, and ties the other loose end onto
John's boat and gently places the lead into the water. Determine the smallest amount of lead (mass) that
will be enough to sink John's boat, assuming the specific gravity of wood is 0.5 and the density of the
pond water is equal to the density of pure water

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.