Rather than taking the stairs, Martin gets from the second floor of his house to the first floor by sliding down the banister that is inclined at an angle of 30.0°
to the horizontal. a) If Martin has a mass of 45 kg and the coefficient of sliding
friction between Martin and the banister is 0.20, what is the force of friction
impeding Martin’s motion down the banister? b) If the banister is made
steeper (inclined at a larger angle), will this have any effect on the force of
friction? If so, what?

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.

I’m good with pshycology