The force exerted by objects outside the system on the particles in the system

The interaction of each particle in the particle system

center of mass distribution of object

Center of mass motion

F=ma=mdv/dt=d(mv)/dt=dp/dt

The impulse of the net external force experienced by an object during motion is equal to the increment of the momentum of the object

During a certain period of time, all external forces acting on the particle will act at the same time The vector sum of the impulses is equal to the increment of the total momentum of the particle system

If the vector sum of the external forces on the system is zero, then the system The total momentum of the system remains unchanged

L=r✖P

dLldt=rxF M=rxF M=dL/dt

If the external force acting on the particle exerts a moment (rx) on a given point O F) is zero, then the particle pair is. The angular momentum remains constant during motion Change

The product of the projection of the force in the displacement direction and the magnitude of the displacement achievement A=Fr

power

Work W

Power P

kinetic energy

Kinetic energy theorem

conservative force

non-conservative force

The total work done by a pair of action and reaction forces always has the same choice-independent invariant properties

The work done by a pair of conservative internal forces is equal to the decrease in potential energy of the system (or the increase in potential energy potential energy

particle system

The sum of the work done by the external and internal forces of the system is equal to the increment of the kinetic energy of the system

When the system changes from state 1 to state 2, the increment of its mechanical energy, etc. The sum of the work done by external forces and the work done by non-conservative internal forces

If only conservative forces do work in a system, other internal forces and all external forces If no force does any work, the kinetic energy and potential energy of each object in the system can interact with each other. conversion, but the total value of mechanical energy remains unchanged

When an isolated system undergoes any change, all the energy of the system The sum is constant, energy can only be converted from one form to another formula or passed from one object to another within the system

Conservation of mechanical energy in point systems

Conservation of momentum of a system of particles

conservation of angular momentum

Conservation of energy

m1v1=m2v2