Where You Push the Door Decides
Two identical doors, the same number of newtons applied to each, released at the same instant — one push at the handle, the other right beside the hinge. The handle side is away while the other barely stirs, and a push aimed straight into the hinge does nothing at all. Distance, not force, is what the idea of a moment was missing.
Cara memakai simulasi ini
- Press Push both to release two doors with equal forces at different distances
- Load Handle against hinge — 0.88 m against 0.15 m from the axis
- Press Push right on the hinge to apply a force at zero distance
- Try A fair fight, 10 N far out against 60 N close in, and see which wins
Yang perlu diamati
- Equal forces at unequal distances give unequal turning effects every time
- A push directed through the hinge produces no rotation whatever its size
- At the same distance the two doors behave identically, so only the product matters
- A slanted push turns the door more slowly than a square-on one of the same size
- 10 N far out can beat 60 N close in, as long as the products come out that way
Fisika di baliknya
Turning effect is the product of the force and the perpendicular distance from the axis to its line of action: M = F·d. Equal forces at different distances therefore produce quite different moments, and the one applied further out wins. A force whose line of action passes through the hinge has d = 0 and produces no moment at all, however large it is. Slanting the push by θ to the door leaves only the perpendicular component F sin θ contributing, so part of the effort is spent pressing the door against its hinge rather than turning it.