A physicist drives through a stop light. When he is pulled over, he tells the police officer that the Doppler shift made the red light of wavelength 635 nm appear green to him, with a wavelength of 550 nm. The police officer writes out a traffic citation for speeding. How fast was the physicist traveling, according to his own testimony

Ateacher gives students four liquids commonly found in the kitchen - vinegar, apple juice, dish detergent, and milk - and ph indicator strips, which measure acidity. the teacher asks the students to put the liquids in order from most acidic to most basic. what type of investigation could the students conduct to determine the correct order for the liquids?