Why is a saying about cattle correct?

Because the velocity is not directly related to the resultant force on the object. The resultant external force is only directly related to the acceleration of the object, the force is the cause of the acceleration of the object, and the acceleration of the object is generated by the action of the external force; Acceleration is not necessarily related to velocity, and when the acceleration is large, the velocity can be very small; When the velocity is high, the acceleration can also be small. The velocity of a ball bouncing repeatedly on the ground is close to zero (or from downward velocity to zero and then upward velocity in a very short period of time) in contact with the ground, but the acceleration is great because the velocity changes dramatically in a very short period of time.

A racing car that travels at a constant speed in a straight line at high speed has a large speed, but because it is driving at a constant speed, the resultant external force is 0, and the change in speed is zero, so its acceleration is also zero. Reference Encyclopedia - Acceleration.

Trouble, thanks!

For example, if an object is moving, if you pull it with the opposite force, the velocity will decrease, so when the resultant force is maximum, the velocity can be 0, and if the object starts to move from a stationary external force, and the force is decreasing, the acceleration will decrease, but the velocity is increasing, and the velocity is increasing, and the velocity is 0, the velocity can be maximum.

Upstairs is wrong, and the cow is also true in the special theory of relativity, that is, it is also true at the speed of light.

However, this is not true in the strong gravitational field (where general relativity plays a major role) and in the microscopic field (where quantum theory plays a major role).

Established in macro and low-speed conditions.

Except when the speed is close to the speed of light.

The law of the ox and the law of the ox are two different laws, the law of the ox is mainly about the inertia of the object, while the law of the ox is about the force of the object.

Any object is subjected to force.

If there is no external force, the object may be stationary, so the above statement is wrong.

Inertia is the property of the object itself and has nothing to do with external forces, hehe.

The relationship between the second and third laws in thermodynamics is not a unified concept.

After eliminating all impossibilities, the remaining impossibilities are also the truth.

At any given moment, the arrow is "both in this position and not in this position", it always has a velocity vector, and it cannot be said that it is stationary.

Time cannot be subdivided infinitely, so Zeno's assumption is wrong.

Zeno's paradox is not true, materialist dialectics tells us that matter is in motion, that there is no such thing as absolute rest.

The first law says that an object maintains its original state of motion without force, i.e., it is at rest or in a straight line at a constant speed. It's tried and tested. Objects moving at ordinary speed obey this law.

"An arrow is stationary at some point during flight"

Regardless of what happens later, this sentence is wrong.

Any moment is in motion.

No, you mean when f=0, a=0, so keep the inertia? This is one of the aspects of the law of inertia.

There are three possibilities, the object is not subjected to an external force, or every external force experienced by the object is perpendicular to the direction of the object's motion, or the resultant force of all the external forces of the object is perpendicular to the direction of the object's motion.

If the object is moving in a straight line at a uniform speed and is to remain in motion, then the vector sum of the vectors of the forces that are not subjected to the force or the forces experienced in the direction of motion is zero.

Due to inertia, the object will remain in its original state of motion in the absence of external force.

Wrong, it will only slow down and move forward, because there is no outside force to propuls it, only air resistance. Newton's first law is the law of inertia, all objects have the property of keeping their motion unchanged until there is an external force to change its motion, but when the bullet leaves the muzzle, it is only resisted by the Zen orange air, which is the opposite force to its motion, so it will slow down.

This is clearly the second law, and the first law seems to be that force is the cause of changing motion.

What is Newton's first law.

The "external force" here refers to the force of the object in addition to the force that was originally received (for example, the car was not originally only traction, but after encountering the rough template, there is friction, and the external force here is the friction force) Imagine that if the school bus is not affected by friction and there is no other external force, then the school bus will not be able to move at a uniform speed, and this is also the reason for staying stationary.

Classmate, I typed so many words, you just me, it's not easy.