Which of the following statements are true? a) light waves are not true waves. b)sound waves can travel through liquids. c)waves can only move matter up and down or from side to side. d) sound waves cannot travel through empty space. e) light waves need matter in order to travel

To travel at constant speed, a car engine provides 24kw of useful power. the driving force on the car is 600n. at what speed does it travel?

What are the applications of electromagnetic waves

6–43 a food department is kept at 2128c by a refrigerator in an environment at 308c. the total heat gain to the food department is estimated to be 3300 kj/h and the heat rejection in the condenser is 4800 kj/h. determine the power input to the compressor, in kw and the cop of the refrigerator.