In the non-inertial frame of linear motion, the inertial force F* on the particle is opposite to the acceleration a of the non-inertial frame, and is equal to the product of the mass m of the particle and the acceleration a of the non-inertial frame, that is

Manifestation: leaning forward and backward, overweight and weightlessness, tidal phenomena

Condition: a non-inertial frame that rotates at a constant speed relative to the inertial frame

Kinetic equations:

Manifestation: apparent gravity, lost weight (South Africa bound for the equator)

Condition: The particle moves relative to the rotating reference system

Kinetic equations:

Coriolis acceleration is not caused by the Coriolis force

Reflection: Earth's rotation, northeast trade winds, typhoon formation, Falling to the east (Northern Hemisphere), washed by rivers

Coriolis force in the Northern Hemisphere: Looking along the direction of motion of an object, it always points to the right. The opposite is true for the Southern Hemisphere.

Particle system: A system composed of several interacting particles.

Internal force: the interaction force between the particles in the system

External force: the force exerted by other objects outside the system on any particle in the system

Only external forces contribute to the total momentum change of the system, Internal forces do not contribute to the total momentum change of the system. But internal forces play a role in the distribution of momentum within the system.

momentum theorem

Newton's second law only applies to particles, The momentum theorem applies to both particles and systems of particles

Centroid

Center of mass motion theorem

Center of mass coordinate system: with the center of mass as the origin, the coordinate axis is always parallel to the basic reference system

The momentum of the particle system relative to the center-of-mass coordinate system is always zero.

condition

The law of conservation of momentum holds for all inertial systems, However, when solving specific problems, the momentum of each particle should be relative to the same inertial system.

Momentum conservation can hold in a certain direction

The element impulse of the force within dt

The impulse of the force in the time interval t-t0

average force

Direction of impulse: direction of velocity increment

If the kinematic equation of the force is known, integral calculation is required

Kinetic equations:

Particle dynamics component formula

circular motion

Condition of particle equilibrium: When the particle is in equilibrium, the net force acting on the particle is equal to zero.

Particle equilibrium equation:

gravity and weight

Spring elastic force

electrostatic field force

Lorentz force

tension in rope

Supporting force of supporting surface

Friction

Mass is a measure of inertia

Operational definition of quality:

In classical mechanics, mass is a constant

In relativistic mechanics, mass increases with velocity, i.e.

momentum

When the force-receiving object is regarded as a particle, the force can be measured by the rate of change of the momentum of the force-receiving object.

The Momentum Theorem of a Point

Newton's second law

Newton's third law

Any inertial reference system is equal or equal in the face of Newton's dynamic laws.

For describing the laws of mechanics, all inertial systems are equivalent

A frame of reference relative to an isolated particle that is at rest or moving in a uniform straight line

A reference frame that moves in a straight line at a uniform speed relative to the inertial frame