If an object moves twice as fast how do you think its energy changes? halves
doesn't change
doubles
quadruples

Explain why electric current cannot exist if a current doesn't have a voltage source.

Mixing salt in water is an example of physical change

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.