# Does drag produce heat?

When a solid object moves through a fluid drag is produced. Does this drag produce heat?

I believe drag should produce heat as it is the friction between fluid and surface of object. Is this true or not?

• yeah! it is true Nov 6 '14 at 5:04

The first law of thermodynamics states, that $E_{int}=W+Q$.
Meaning, any work done by (or on) an object results in changing its internal energy (temperature). If, of course, $Q$ doesn't balance it out (this is when $Q=-W$). You need to have a well insulated object (when $Q=0$) and you'll definitely know, that work will result in temperature change.