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15. give an example for some particles or waves that are moving faster than light in everyday life 16. what is a laser? 17. what is an oscilloscope? 18. what does it means practically that nothing is faster than light in vacuum? 19. what is vacuum?

Which articulations allow for greatest range of motion?

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.