Four small 1.0 g spheres each charged to +10.0 nC (aka point charges) are arranged at the corners of a 1.0 cm by 1.0 cm square. They are released simultaneously and are allowed to move away from each other. What is the final speed of each sphere when they are very far apart? (Give answer in m/s).

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? the cloud is extremely hot. the cloud is visible primarily because it reflects light from nearby stars. the cloud is cool and lies between you and a hot star. the cloud is cool and very dense, so that you cannot see any objects that lie behind it.