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Decomposition idea of physical force - there are many forces acting on an object. If a force is selected, how to divide the force? 1. Why is the decomposition of academic ability horizontal and vertical at present? (orthogonal decomposition) but I always feel that this method is not acceptable 2. How to decompose a force without knowing its composition?
1. Because at present (especially in grade one of senior high school), the mechanical analysis mainly focuses on n (supporting force), Mg (gravity), f (resistance and friction), t (tension), f (thrust or pressure and component force) which are horizontal or vertical to the contact surface
For example, the study of motion in a plane, pressure and gravity perpendicular to the plane, resistance and thrust or pull parallel to the plane
When the inclined plane is studied, the pressure and gravity are perpendicular to the contact surface, and the resistance and thrust are parallel to the contact surface
Therefore, orthogonal decomposition is a convenient method to decompose force, and it is easy for most beginners
Frankly speaking, it is the mainstream of physical mechanics analysis. You should learn to adapt to the mainstream
2. If you don't know anything about a force environment, it's useless for the immortal to come, because there is no clue
Generally speaking, the decomposition force takes an object as a point. Then you need to do the following
① If the particle is in contact with other objects, and if the particle moves after removing the object in contact with the particle, then the particle has pressure on the object, and the direction is perpendicular to the contact surface
② If the particle is stationary in a direction other than the vertical direction, the object is subject to friction or resistance on the axis, and the force opposite to the direction of friction or resistance
③ If an object is pulled by the rope and the rope remains taut, the object will be pulled along the direction of the rope. If the rope is "just taut", then analyze whether the object has other force (or component force) in the direction of taut with the rope. If it has and can make the object just stand still in this direction, the object will not be pulled by the rope
④ If the object is pulled by the spring and the spring is deformed, it will be pulled (when the spring is longer) or pushed (when the spring is shorter) by the spring in this direction. If the spring is not deformed, there is no need to study
⑤ If an object is pulled by a hard bar, it is necessary to analyze whether the object is forced in a certain direction. If it is forced, the elastic force of the hard bar is opposite to the direction of the force, regardless of whether the direction of the force is in the same direction as the hard bar
⑥ The force on the inclined plane should use trigonometric function, I don't need to say that, right?
It's a bit wordy,
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