A300 g hockey puck is shot across an ice-covered pond. before the puck was hit, it was at rest; after the hit, the puck has a speed of 40 m/s, and comes to rest after going a distance of 30 m. (a) describe how the energy of the puck changes over time, giving the numerical values of any work or energy involved. (b) find the magnitude of the net friction force.

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.