Arock at the top of a 20 meter tall hill. the rock has a mass of 10 kg. how much potentail energy does it have?

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

What is the role of lenses in microscopy?