Got a broken door hinge again? I can show you a quick fix that saves you time and money.

Sure thing, let’s keep it simple – grab a napkin, draw a big rectangle for the frame, a smaller one for the door. Put a hinge line between them, add an arrow for the applied torque on the door side, and another arrow in the opposite direction on the hinge side. Label the first as τapp and the second as τhinge. The difference between the two gives you the net torque, which is what’s actually doing the work. In terms of entropy, think of it as the extra “mess” you get from friction and wear – the more torque you need to keep things moving, the more energy gets dissipated as heat, bumping up the entropy. If you want to cut the friction, just keep the hinge lubricated and the system will stay calmer, lower entropy, and you’ll be happier with the door’s life span.