1. Physicists realized that Newton's laws of motion were not adequate under all circumstances around the year a) 1800 b) 1850 c) 1900 2. In which arena did measurements reveal the need for new physical principles? a) subatomic particles b) radio waves c) fluid mechanics 3. A critical experiment was performed by Michelson and _________ a) Lorentz b) Einstein c) Morley