Usually start on the internet, there is bound to be something or a form of information on it.
When the object is at the top of the hill it has the most potential energy. If it is sitting still, it has no kinetic energy. As the object begins to roll down the hill, it loses potential energy, but gains kinetic energy. The potential energy of the position of the object at the top of the hill is getting converted into kinetic energy. Hope this helped. :)
When 'The big bang' happened lots of large pieces of molten rock was flying around the solar system. As the rocks crashed together they got bigger and as the got bigger they attracted more rocks. Some scientists think that a large piece of molten rock hit the still developing Earth and created the Moon. This impact also caused the Earths angled spin. The Moon got trapped in Earth's orbit and has stayed ever since. Small astroids have hit the Moon causing craters. The Earth doesn't get hit as much because of our thicker atmosphere. Hope this helps!