Tina and her puppy are tugging on a rope, each pulling on opposite ends. when is tina doing work?

Work is classified as anything the exerts energy from a system. Therefore, during the entire activity as Tina both holds the rope and actively pulls on the rope with her puppy she is completing work. Tina also does work when she walks toward and way from her puppy.

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.