1kg of a fluid is contained in a cylinder at an initial pressure of 20bar. The fluid is allowed to expand reversibly behind a piston according to the c = pv² until the volume is doubled. The
fuid is then cooled reversibly at constant pressure until the volume is doubled. The fluid is
then cooled reversibly at a constant pressure until the piston regains its original position heat
is then supplied reversibly with the piston firmly locked in position until the pressure rises to
the original value of 20bar. Calculate the networkdone by the fluid, for an initial volume of
0.05m³.​

B

Explanation:

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.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west