Lurch
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A roller support works similar to a skateboard. The wheels are roller supports, they support your weight against gravity, but when you push to the side, you move. Ignoring frictions, a roller support gives no resistance to movement in the horizontal.
A hinged support works similar to a door hinge. If you push the door a certain way (at the doorknob), the door opens because the force is not resisted by the hinge and the support is free to rotate, However, it resists forces pushed into the door near the hinge, meaning the hinge support resists movement in horizontal and vertical motions, but allows it to rotate.
There is also a third type of support - a 'fixed' or rigid support. It opposes all three (rotation, horizontal movement and vertical movement), and is similar to a nail pounded into a piece of wood. You can't pull it out, you can't push it around along the length of the wood, and if you try to "open" the nail, it resists.
16 years ago
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