It is easier to to pull the bucket of water from well until it is inside the water but difficult out of water? why

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

What is the angular momentum of the bar about the axle?

Estimate the change in the gibbs energy and molar gibbs energy of 1.0dm3 of octane when the pressure acting on it is increased from 1.0 atm to 100 atm. the mass density of octane is 0.703 g cm−3