Q: a: sarah and maria made a telephone using two cans and a string. it was a very long string. maria went upstairs in her house and sarah stayed downstairs. maria spoke softly into the can. "i can hear you! ' sarah said back. how can this happen? a) sound waves travel through a vacuum. b) sound waves travel from high to low. c) sound waves travel through solids like the string. d) maria talked so loudly that sarah could hear her without the phone.

In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully cooled rubidium atoms to the 20-200 nk temperature range. assuming (incorrectly) that the rubidium atoms behave liké particles of a classical ideal gas, calculate the rms speed of a rubidium atom at a temperature of 112.0 nk. in the experiments one particular isotope of rubidium was used, rubidium-87. the molar mass of this isotope is 86.91 q/mol. tries 0/20 submit answer

Adding more pulleys to a system of pulleys needed to lift an object. a. increases the force b. decreases the force c. increases the amount of work d. decreases the amount of work

Which describes increasing the efficiency of energy resource