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: http://zebu.uoregon.edu/1995/ph161/friction.html
Дата изменения: Tue Sep 23 15:28:04 1997 Дата индексирования: Tue Oct 2 05:27:33 2012 Кодировка: Поисковые слова: jet |
The maximum force of static friction that exists between two surfaces is proportional to the normal force and mostly independent of area of contact. This situation is shown here: N = the total normal force (force perpendicular to the horizontal surface) which is essentially the weight of the object. The coefficient in that equation is called the coeffecient of static friction and that depends on the material:
The following example (which we will do in class) demonstrates the general rule that friction is not dependent on total area of contact
Although their are 5 symbols only three of them are active: You will either get:
You may adjust the angle of the incline. The four vectors that represent the gravitional force (red), the normal force (blue), the frictional force (green) which opposes the motoin, and the component of the gravitational force (white) which is trying to pull the block down. You can adjust the angle such that the green vector is bigger than the white vector and therefore nothing will happen. After you have set the angle, hit the start button and watch the block slide down the incline and watch how the vector forces change slightly. The simulation runs for 10 seconds; this may not be long enough to cause the block to completely slide down.