About Newton s First Law How does the uniform motion of an object in the oblique direction maintain

There are 2 points to determine for this topic:

One. The object weighs 10 Newtons, this force is gravity, the direction of gravity is always vertical downward, whether it is flat on the ground or a 45-degree inclined plane or a 60-degree inclined plane, the gravity of the object is always vertical downward.

Two. The object moves in a uniform linear motion, which means that the external force on the object at this time is zero, that is, the sum of all external forces is zero.

From the above 2 points, it is very clear that the object is only affected by gravity (the 45-degree slope of this question is deliberately misleading, remember that the direction of gravity is always vertical downward, don't be deceived by that 45 degrees), the parameter of this gravity is 10n, and the direction is vertically downward. Then, to make the object move in a straight line at a uniform speed, it is to make the sum of the external forces zero, that is, to add a force equal to the magnitude of gravity and in the opposite direction to the object - so that it is very clear, the magnitude is 10n, and the direction is opposite to gravity, of course, it is vertically upward.

10 times the force of the root number 2 N, at an angle of 45° to the horizontal plane.

Splitting the diagonal force into vertical and horizontal forces, and balancing the vertical and gravitational forces, just gives you this hint, and the rest is up to you.

1. Uniform linear motion so the force must be balanced, f=mg, and the direction is vertical and upward.

20n。Vertically up.

f=g is also a balanced force, so it is vertically upward

Analysis: According to the scope of application of the law of motion of the Ox Chanton: (1) it is only applicable to objects moving at low speed (the speed is lower than the speed of light); (2) It only applies to macroscopic objects, and Newton's second law does not apply to microscopic atoms; Newton's second final conjecture can only be applied to the low-velocity motion of macroscopic objects

So the answer is: macro; Low Speed Comments: This question examines the scope of application of Newton's second law, knowing that Newton's second law does not apply to objects moving at high speeds, as well as microscopic particles

The statement about Newton's laws of motion is incorrect ().

a.Newton's third law does not require that the frame of reference must be an inertial frame.

b.Newton's theorem of motion applies to any situation.

c.The second law of Niu Xuyanton is vector.

d.Newton's first statute defines an important frame of reference for the class of slow fronts, i.e., inertial frames.

Correct answer: B

The time t of the ball tube to Q

Tube acceleration a1 = (mgsin60°- mgcos60°) m=s1=(1 2)a1t 2

t=√(2s/a1)=√（2*

m is the mass of the pellet. Since the tube has acceleration, the non-inertial frame is a force using Newton's two laws, and an additional inertial force ma1 must be added to the ball.

The upward acceleration of the ball.

a2=(ma1-mgsin60)/m=(

The displacement of the ball relative to the tube does not exceed when t=2s, and the minimum initial velocity is v0s2=vot-(1 2)a2t 2

v0=(s2+(1/2)a2t^2)/t =(

Starting from the time, the sliding acceleration a of the tube is g*sin60° root number (3)-1, and because s=(a*t 2) 2, the two formulas can obtain t, and then v0*t+(g*sin60°*t 2) 2=sv0 can be found.

Consider: How many forces does a person experience when standing on an elevator? There are only two:

Gravity and support, these two forces are undoubtedly the balancing force, so relative to the elevator, people are under the action of the balancing force to remain stationary. The elevator accelerates the linear motion relative to the ground, and the person is standing on the elevator, so by the balance force, the elevator should be used as a reference when studying people. As for the feeling that people are aggravating (reducing) themselves, it is because they are in a non-inertial frame of reference to introduce non-inertial forces, which is a university course, and there is no need to understand it now.

To be honest, it is impossible to understand)

In this example, the person and the elevator are a whole, and this whole is accelerated because of the unbalanced force.

If we have to use the elevator as a reference to describe the movement of people, because people and elevators have the same acceleration, after neutralization, people are stationary relative to the elevator, which conforms to Newton's first law of motion.

People can feel weightless or overweight, because the force is the cause of acceleration, this is not only the subjective feeling of people, at this time with a spring scale weighing, it is indeed a reduction or weight, the weight (gravity) that is aggravated or reduced, is used to produce acceleration.

I don't think it's necessary to say that.

The stationary and uniform linear motion itself is itself a relative concept, and indeed people are subjected to unbalanced forces, which are relative to the Earth, and the gravity of the Earth is not equal to the elevator support force that people receive.

But relative to the elevator, people are subject to the balance of the force, why do you say that, even if people feel that they are weightless or weightless, but the elevator to give people support and people to the elevator pressure is a pair of balance force.

The reference you choose changes, and when a person is standing on an elevator that is moving upward (downward) at an accelerated pace, your reference is an object other than the elevator. The person is stationary relative to the elevator, and the reference you choose is the elevator. In that is, you can do a force analysis on people and a force analysis on elevators.

The so-called overweight and weightlessness phenomenon when taking the elevator, assuming upward acceleration, the vertical direction of the motion state changes, f ma, indicating the vertical direction of the force, that is, the elevator to the person support force minus the person's own gravity!

And personally, I think that Newton's first law is established in a stationary inertial frame of reference!

First of all, force is not defined in terms of mass and acceleration, you have to figure out the sequence, it is force and mass to define acceleration, don't reverse it, it is f that is generated first, and there is m, then a will be generated, not a and m will produce f.

Secondly, when a particle is far enough away from other particles, this sentence is just an assumption, because the distance is far enough, so it can be approximated to ignore some tiny things, and it is approximately equal, not completely equivalent.

Circular motion is not a simple motion at all, the uniform velocity in the uniform circumference just means that it is not subject to any force in the tangent direction of the circumference and moves at a uniform speed, which is not a standard uniform motion, because the direction of this velocity is changing, and the uniform motion cannot change the direction. The external force that changes direction, that is, the centripetal force, exists in the straight line with the vertical tangent pointing to the center of the circle, this force has always existed and the magnitude is constant, but the direction also changes all the time, without the existence of this force, the particle will be thrown out in a uniform linear motion along the tangent direction. In order for a circle to turn, it is necessary to connect the center and the circumference together, and these connected materials are the providers of this force, just like a rope tied to an iron ball, and when it is rotated, the rope may be broken, and the formal force of the rope will be broken.

Uniform circular motion is a kind of combined motion, of course, different from uniform motion, it is a special acceleration motion, this "acceleration" is not reflected in the magnitude of the velocity, but in the direction, the velocity is a vector, and any change of the two is considered a change. This is an ideal motion, and you can understand it as a uniform circular motion.

Your understanding of physics is still not deep enough, and I hope you will continue to work hard.

A wheel that rotates at a constant speed is stationary if it is considered to be an object. And if you want to divide it into an infinite number of particles, then each particle, relative to the center, has a centripetal acceleration, and the acceleration should be formed by the force between the molecules inside the object.

Any point on the wheel cannot be stationary relative to the center of the wheel, because all you know is that the magnitude of the velocity does not change, but the direction of the velocity changes. Velocity is a vector quantity that contains magnitude and direction. So there is something wrong with your understanding.

Uniform circular motion is a variable acceleration motion with the direction of acceleration pointing towards the center of the circle.

Analyze a particle on a wheel that is centripetal by the tension of other particles on the wheel.

If you want to look at the wheel as a particle, you can't analyze the rotation of the wheel anymore, because the point can't rotate itself.

I don't understand what to divide ......Uniform circular motion is uniform circular motion, and the book should also be specially separated to talk about a point in the circumference Its motion can be represented by tangential acceleration and normal acceleration That is to say, the tangential acceleration of uniform circular motion is 0 (?)

Uniform circular motion can be referred to as "uniform linear velocity circular motion" or "uniform angular velocity circular motion". It is characterized by the fact that the magnitude of the combined external force does not change, and the direction changes at all times and points to the center of the circle at all times, so it is not a uniform speed movement. Acceleration motion is divided into uniform acceleration and variable acceleration motion, and what the landlord said is not very accurate.

Uniform acceleration is the motion in which the acceleration remains constant, and variable acceleration is the motion in which the acceleration changes at the moment. The acceleration of a uniform circular motion does not change in magnitude and direction from moment to time, so it does not belong to this category. I don't know if this explanation suits your problem.

Your question is: why is a uniform circular motion an accelerated motion.

1. The wheels turn. You have introduced Newton's first law in a large article, and I am sorry to tell you that this is purely redundant. Because, Niu Yi is applicable to particles, so you have to divide the wheel into countless points to consider, (otherwise, please don't use Niu Yi) In the end, you will find that each mass point is a centripetal force....

The second way of expression is your own understanding, there is no such expression in the book, Newton's first law is also called the law of inertia, you are confusing the knowledge in the book, it is recommended to read more in the book. Newton's first law has nothing to do with the second way of expression. And, you're confusing Newton's laws with frames of reference!

Circular motion, whether it is a uniform velocity or a variable beam motion, is an accelerated motion. If v≠0 is said then there must be a centripetal force f and there is a centripetal acceleration a, so the circular motion is an additive motion. If v=0, the object is at rest, how can it be said to be in motion.

Here, it is recommended that students read the book carefully, do not confuse the knowledge, and digest the knowledge of the frame of reference, Newton's first law, and circular motion!

Bull's law: Any object must remain in a uniform linear motion or at rest until an external force forces it to change its state of motion.

In the process of a person who is moving, he stops because there is friction between the person and the ground, and friction is the external force in the law. In other words, the statement 'stop by yourself' is not true, it is friction that makes you stop. There are already external forces involved, and the state of movement has changed.

If you're on the ice, there's less friction, and correspondingly, it's harder if you want to stop.

If people are in the vacuum of the universe, they are truly free from external forces, and then they will be completely unable to change their state of motion. Therefore, the astronaut who is out of the capsule will have a rope to connect himself to the spacecraft, and in the event of an accident, he can adjust the length of the rope to obtain the pull of the rope, change his motion state, and return to the cabin.

Newton's first law refers to the fact that an object will remain in a state of uniform linear motion or rest without the action of force, and people can be used as moving objects, but the person who moves in a uniform straight line stops by himself, and there is a force made by himself to prevent him from moving forward, because he has changed the original state of motion due to the action of an external force, so it does not violate Newton's first law.

That's an interesting question! Man is just an ordinary object!

Models built by mathematics or physics are actually designed to better solve complex problems in our lives. The same is true for uniform linear motion, when you say people are doing linear motion, do you mean people walking? If so, then the problem is even more.

Man has to overcome air resistance, overcome the gravitational pull of the earth, friction ....... The most important of these is"Reference object (system)."！The person you are talking about moving in a straight line at a uniform speed is relative to you, and he stops at least because of the static friction between the ground and the soles of his shoes.

Newton's first law is very bullish! The other is called the Law of Gravitation! Does it show that it is widely used in people's real life?

On the road to acquiring knowledge, the new network puts all the things that human cognition is in front of us! In addition to Euclidean geometry, there are also Roche geometry and Riemannian geometry, all of which have their own application space. The problems solved by Euclidean geometry are:

The spatial distance is neither too big nor small, and people can reach it.

Humanity is a miracle! The development of human civilization to the present time in space, and the flight of the artificial astronomical voyager from the solar system are the result of the accumulation of wisdom and human knowledge, I hope you can enjoy the process!

You think you can stop, isn't it because of the friction of the ground? See for yourself how hard it is to stop when you're skating and the friction is drastically reduced because of the wheels on your feet.

Newton's second law can only be applied to the low-velocity motion of macroscopic objects

So the answer is: macro; Low speed