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1.

Suppose that a particle subjected to a certain force moves from the initial position to the final position, and the work done by the force is independent of the moving path, then the force is called conservative force, also known as conservative force. Equivalently, if a particle moves from a certain position, passes through a closed path and returns to its original position, then the mechanical work done by the conservative force acting on the particle (the integral of the conservative force over the whole closed path) is equal to zero

For example, gravity, spring force, magnetic field force, electric field force and so on are conservative forces; Friction and air resistance are typical non conservative forces

extended data:

conservative force judgment method:

if and only if the curl of the field vector is zero, we also call it irrotational field, for example, electrostatic field is irrotational field, so it is conservative field

1. For one-dimensional motion, all forces of single valued function of position X are conservative. For example, the elastic force F = f (x) = - K (x-x0) obeying Hooke's law is a single valued function of X, so it is a conservative force

For more than one-dimensional motion, the force whose magnitude and direction are independent of position, such as gravity g = mg, is conservative

3. If there is a center O in space, the force F on the object (particle) P at any position is the same as the direction of "vector OP" (repulsive force) or the opposite (attractive force), and its magnitude is a single valued function of the distance r = scalar OP, then this force is called "central force". For example, gravitation is central force, and all central forces are conservative forces

2.

In a physical system, if a particle moves from the starting point to the ending point, e to a force, and the work done by the force does not change e to different paths, then the force is called a conservative force. If all forces in a physical system are conservative forces, the system is called conservative system

the work of conservative force has nothing to do with the path the object moves through, but only with the position of the starting point and the ending point of the moving object, and of course also with the nature of the conservative force field

extended data

1. The amount of work done by the conservative force on the object depends on the initial and final position of the object. If under the action of this force, the motion of the object detours along the closed route and returns to the initial position, the work done is zero. Gravity and elasticity are conservative forces

The work done by the dissipative force can not be determined by the starting and ending position of the object, but is related to the motion path of the object. Under the same conditions, the longer the motion path of the object, the more work will be done. Friction and viscous force belong to dissipative force

The difference of work done by conservative force and dissipative force is related to their own characteristics. After the system of objects is determined, the conservative force has nothing to do with the motion of the objects. Its size is determined by the relative position of the interacting objects, and its direction is always on the line between the two interacting objects

for example, after an object is determined, the magnitude of gravity depends on its height from the ground, and the direction is vertical and downward, which has nothing to do with the speed of the object, and has nothing to do with the magnitude and direction of the object's speed. The magnitude and direction of the dissipative force change with the change of the velocity and direction of the object

for example, the direction of the resistance of air to a moving object changes with the direction of the object's motion, and its size increases with the increase of the speed of the object's motion

The conservative force is closely related to the potential energy of the system. If the conservative force does positive work, the potential energy of the system decreases; On the contrary, the potential energy of the system increases. Moreover, the work and energy difference between the two positions are constant. Therefore, the existence of conservative forces between objects is the condition for the system of objects to have potential energy. The mechanical energy of the objects in the system is conserved when they are only subjected to conservative forces

The dissipative force is not like the conservative force. For two positions, there is no definite value of the work done by the force on the object, so there is no certain energy difference between the corresponding two positions. So the dissipative force has no relation with the potential energy of the material system. But it involves another form of energy. If the objects of the system are only affected by conservative and dissipative forces, then the total energy of the system, including the corresponding form of energy and mechanical energy, is still conserved