How Does Polishing Affect Heat Flow in a Gold Ring?

[musicmar]

Homework Statement

You are polishing a 10.0 g gold ring. (treat as an ideal solid). After doing this for a minute, you find that the ring is hot, having increased the temperature by 15 deg C. Calculate the heat that flows into or out of the system and specify which direction.

Homework Equations

ΔE_therm=Q_in+W_on
ΔE_therm=nCΔT
C_ideal=3R

The Attempt at a Solution

nCΔT=Q_in+W_on

I can calculate nCΔT, but I don't know what to do about the work. Once I find the work done, then I can find Q.

 

[Mapes]

Mechanical work can be written as -P\Delta V, where P is the pressure and \Delta V is the volume change. Has the ring changed volume?

 

[musicmar]

Not that we know of. So, does that mean that there is no work done, so ΔE_therm=Q_in?

 

[Mapes]

Sure.