Cas asks:

What is the short­cut key to force quit an appli­ca­tion on a Mac?

Short answer: ⌘ + option + escape

Long answer: Although many Mac zealots would say oth­er­wise, Apple Mac com­put­ers are not per­fect. Occa­sion­ally, appli­ca­tions will quit work­ing and you’re stuck star­ing at what I like to call, “the Rain­bow wheel Of Death”, or ROD for short. You’ll know him when you see him!

Often, a lit­tle patience will pay off and the appli­ca­tion will resume, but if you know it’s crashed, or you’re impa­tient, force quit the appli­ca­tion. Hit the key combo above, and the ensu­ing dia­log will list your appli­ca­tions AND tell you if one is not respond­ing. You can even force quit (or relaunch) the finder through the force quit dialog.

Alter­na­tively, you can also find “Force Quit” under the apple in the title bar, or by hold­ing the left mouse but­ton on the guilty application’s icon in the dock.