Discussion topicselect a musical instrument. research theinstrument and explain how it works in terms ofsound production and resonance. describe how amusician can vary the pitch and loudness of thenotes. explain why different types of musicalinstruments sound different, even though theyplay the same notes.

First answer marked as brainiest which is the correct equation describing the first law of thermodynamics? a) when the internal energy of a system changes, it equals the amount of heat added plus the work done. b) when work is done by the piston, it is equal to the heat added plus the change in internal energy of the system. c) when heat is added to the system, it is equal to the amount of work done by the piston plus the change in internal energy of the system.