Two balls of mass 0.4 kg and 0.8 kg are connected by a low-mass spring. This device is thrown through the air with low speed, so air resistance is negligible. The motion is complicated: the balls whirl around each other, and at the same time the system vibrates, with continually changing stretch of the spring. At a particular instant, the 0.4 kg ball has a velocity <8, -5, 8> m/s and the 0.8 kg ball has a velocity <3, 2, 4> m/s. (a) At this instant, what is the total momentum of the device?

(b) What is the net gravitational (vector) force exerted by the Earth on the device?

(c) At a time 0.10 seconds later, what is the total momentum of the device?

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.