A van der waals gas undergoes an isothermal expansion from specific volume v1 to specific volume v2. 1) Calculate the change in the specific helmholtz function for this process.2) Calculate the change in the specific internal energy U for this process in terms of v1 and v2 using uqation F=U +T(partia F/ partia T)V.

the independent variable, or the one that is intentionally manipulated is the speed.

change tension

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

b.a device that inputs heat into a cool object