1. An astronaut with mass 80.0 kg is tethered by a strong rope to an orbiting space shuttle.
The mass of the shuttle is 8.55x10^4 kg, and the mass of the rope can be ignored. The shuttle
is far from the earth and moon, so the gravitational forces on it and the astronaut are
negligible. Both the shuttle and the astronaut are initially at rest relative to each other. The
astronaut then pulls on the rope with a force of 90 N.
a) What force does the rope exert on the astronaut?
b) What is the astronaut's acceleration?
c) What force does the rope exert on the shuttle?
d) What is the shuttle's acceleration?

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.