Questions about force analysis of objects on Earth

Objects on Earth are subject to the gravitational pull of the Earth and the elastic force (support force) of the Earth, and there are only these two forces. What we call gravity is a manifestation of gravity, which is equal to gravity if and only if it is at the equator or at the poles.

Your understanding is correct, but there are two things to note: 1. Your understanding is based on the geocentric frame of reference. 2. The concept of using gravity is generally in the ground coordinate system, which is considered to be a non-inertial frame of reference, so in this frame of reference, a symbol should be added to the f direction to become (-f direction), which we call the implicated inertial force, which is the product of the non-inertial frame of reference.

Hence in this frame of reference we can say that gravity is the resultant force of the gravitational force and the implicated inertial force. Since the inertial force involved in the general problem is so small, it has only conceptual significance and no calculative significance. Gravity, in order to reflect this concept, treats the acceleration of gravity as a quantity that varies with latitude.

We rarely see the difference in gravitational acceleration at different latitudes, but think that gravitational acceleration is either , or 10ms. This is what is meant by "it is only conceptual, not calculative" (but not absolutely, in special cases it is necessary to consider the gravitational acceleration as a function of latitude). Questions about force analysis of objects on Earth

LRZ that buddy obviously didn't understand what you meant, and he couldn't even understand that you just drew the components, and he was still saying that gravity and centripetal force were just components that couldn't be drawn, so I'm really curious about how he usually does the force analysis questions, and you still have ...... with himAlthough it's been a long time, today I suddenly thought of this question and took a look, mainly on the equator, it's really hard to explain ......On the equator, you should have misinterpreted, it should be F direction = F 10,000 - F branch, F 10,000 = G + F direction, and G = F branch.

Analysis: The force on an object due to the attraction of the earth is called gravity All objects on the surface of the globe and in the vicinity are affected by gravity The force on our earth is gravity Therefore, the answer is: gravity Comments:

This question examines the existence of gravity, and it should be noted that the earth has a gravitational effect on everything around it

The force analysis of the object is as follows:

1) Select and study the hail chaos: that is, determine the object to be analyzed by force. The object of study can be a single object or a systematic combination of objects.

2) Isolated object analysis: The research object is isolated from the surrounding objects, and then the gravity, elastic force, friction force, electric field force, magnetic field force, etc. experienced by the object are analyzed, and the surrounding objects are checked to exert force on it.

3) Draw a schematic diagram of the force: analyze the force in a certain order. Generally, gravity is analyzed first; Then go around the object to find the objects that are in contact with the research object, and analyze the elastic and frictional forces one by one; Finally, other field forces are analyzed.

In the process of force analysis, it is necessary to draw the force diagram while analyzing (develop a good habit of drawing the force diagram).Only draw the physical force, not the effect force.

4) Check whether there is any error in the force analysis: after the force analysis is completed, check whether each force drawn can find out its force object, and check whether the analysis results can make the research object in the motion state given by the title, otherwise, the phenomenon of force leakage, multiple force or wrong force must occur.

Only the forces exerted on the object of study are analyzed, and the forces exerted on other objects are not analyzed. It is important not to mistake the force acting on other objects for the "transfer of force" acting on the object of study.

Only forces named by nature are analyzed, and forces named by effect (gliding force, centripetal force, recovery force) are not analyzed. Every time a hail force is analyzed, the object of the force should be identified to prevent the analysis of some non-existent forces. The resultant force and the component force cannot be the force experienced by the object at the same time.

Definition of force analysis: find out all the external force sources of a specified object (research object) in a specific physical situation, and draw a force diagram, which is force analysis.

The general sequence of force analysis is that the field forces (gravity, electric field, magnetic field) are analyzed first, then the contact forces (elastic force, friction force), and finally the other forces.

Gravity is the gravitational pull of the Earth on you.

and supportnfwithnThe resultant force of the object is followed.

The centripetal force of the Earth's rotationfn, i.e., the vector equation isfnfn, gravity mgwithnIt is the relationship between action and reaction force.

The first thing to explain is gravity, which is the attraction of the earth to objects, so no matter what kind of object, its gravity is vertically downward.

If you want to analyze the force on an object, then you can't just draw the attraction of the earth to it, and this attraction on the object, then it is vertically downward. Then through the gravitational force, the earth has a vertical downward gravitational force on the object, for its attraction, then the object also has an attraction to the earth, and this attraction is acting on the earth, because it is meaningless to analyze an object, the force acting on the earth, so only the gravity of the object is analyzed vertically downward.

In the background of the universe, there is a gravitational force between any two objects, so it is called gravitational force, and the objects on the earth are the same. But gravity is the gravitational force exerted on an object near the ground.

Objects on the ground that have a slightly smaller gravitational force than gravity due to the rotation of the Earth can be ignored.

That is, the gravitational force experienced by objects near the ground, which is gravity, and it is renamed gravity. and is represented by the symbol g.

Gravity is the gravitational pull of the Earth on an object. Objects on the ground have a slightly smaller gravitational force than the Earth's gravitational pull on objects due to the Earth's rotation, but this difference is negligible.

If you study the equation of the centripetal force for circular motion, you can calculate that the centripetal force required for rotation is much less than the gravitational force, so the effect of this rotation factor is negligible.

Free of his truth, those who study physics must be good at asking questions.

1. Your understanding is based on a geocentric frame of reference. 2. The concept of using gravity is generally in the ground coordinate system, which is considered a non-inertial frame of reference, and therefore under this frame of reference.

According to Newton's second law, the force experienced by an object is equal to the product of the mass of the object and the acceleration it has. Therefore, the force f of the influence of the silver nucleus on the movement of the earth in the galaxy is.

The driving force of the earth.

From Eq. (4-6), as long as the mass m of the earth and the values of other parameters in the equation are substituted, the functional relationship between the force f of the earth in motion in the Milky Way and the polar angle of the Earth's orbit is obtained.

According to the data, the average distance between the solar system and the silver core is about 10kpc, which is equivalent to about 3085680000 billion kilometers; take the Earth's orbit around the silver core parameter a = 3085680000 billion kilometers; The circumference of the track is 2.

Earth mass m

kg。Elliptical orbit parameter p (1 e)2

The driving force of the earth.

The values of p, and a, e, and m are substituted into (4-6).

The driving force of the earth.

From the table in Eq. (4-7), the change of the force f on the earth when [0°, 360°] changes are examined (see Table 4-1).

Table 4-1 Relationship between f and .

Note: All values in column F are 1015,a (cos ecos2

2e）/（1＋ecosθ）2

According to Table 4-1, the relationship between f and change in one week is obtained (Figure 4-2).

Figure 4-2 illustrates the following points.

Within a week, there will be two significant changes in the force, one is positive, and the direction is the same as the polar diameter; Once it is negative, the direction is opposite to the polar diameter, that is, the force acting on the earth is manifested in two ways, one is a positive force and the other is a negative force.

The angular range of the negative force is small (102°25 257°35), but the absolute maximum value of the force is large. The angular range of the positive force is large (102°25 102°25), but the absolute maximum value of the force is small.

Since the polar diameter direction is pointed by the silver nucleus towards the direction of the solar system, the positive force is directed towards the earth in the normal direction and acts on the earth, and the negative force is directed towards the silver core and acts on the earth along the direction of the normal of the earth.

Figure 4-2 Earth force analysis diagram.

You should be talking about two questions:

1. Stationary objects on the Earth's surface: gmm r 2 = g + fgmm r 2 – gravitational force.

g – the force of gravity measured by the spring scale.

f - the rotation of the object with the earth and the centripetal force, which is usually ignored, that is, f = 0 Second, the object moves in a circular motion on the ground (or in the air near the earth). (e.g. a thin rope pulling a ball in a circular motion in the air).

At this time, when the object is moving to the highest point, if it is a rope.

The pull force is. 0.Then the centripetal force of the circular motion of the gravitational ball is provided by gravity.

Other common problems include cars crossing arched bridges, and ......... objects moving in a circular motion in a vertical planeAt this time, there is no need to consider the centripetal force required by the object to rotate with the earth!!

Gravitational attraction is related to the mass and distance of an object.

Since the Earth is an ellipsoid slightly flattened from north to south, the gravitational pull of the north and south poles is greater than that at the equator.

The centripetal force is the component of the gravitational force that is generated to counteract the centrifugal force generated by the object with the rotation of the earth. It is related to the linear velocity of the object, the linear velocity of the object at the north and south poles is zero, so the centrifugal force is the smallest, and the corresponding centripetal force is also the smallest.

The linear velocity of an object at the equator is the maximum, so the centrifugal force is the largest, and the corresponding centripetal force is also the largest.

Gravity is another component of gravity after deducting the centripetal force, because the gravitational force is the largest at the north and south poles, and the centripetal force is the smallest, so the gravitational force is the maximum, whereas the equator has the smallest gravitational force due to the smallest gravitational force and the centripetal force is the largest.