You're doing a lot more work than you realize (most of which goes unpaid). This tutorial will have you seeing the world in terms of potentials and energy and work (which is more fun than you can possibly imagine).
Weighing machines of all sorts employ springs that take a certain amount of force to keep compressed or stretched to a certain point. Hooke's law will give us all the tools to weigh in on the subject ourselves and spring into action (yes, the puns are annoying us too)!
If you have ever used a tool of any kind (including the bones in your body), you have employed mechanical advantage. Whether you used an incline plane to drag something off of a pick-up truck, or the back of a hammer to remove a nail, the world of mechanical advantage surrounds us.