Senior 1 Physics. Resultant force, high school physics resultant force formula

<> taking Figure (1) as an example, assuming that the object is stationary on an inclined plane, the object on the inclined plane receives the gravitational force g, the frictional force f along the inclined plane, and the supporting force t on the perpendicular inclined plane, and these three forces are analyzed.

Question 1: When is the direction of the resultant force horizontal?

A: <>

The resultant force in the vertical direction is 0, i.e., t2+f2-g=0;

Horizontal force = f1-t1, and f1 is not equal to t1;

Question 2: When is it along the inclined plane?

A: <>

The resultant force in the direction of the vertical inclined plane is 0, i.e., g2=t;

The force in the inclined direction = f-g1, and f is not equal to g1;

If you don't understand, you can ask

Satisfied, thank you o(o

Quite simply, look at the state of motion of the object:

If the inclined plane is stationary, the object moves in the direction of the inclined plane, and the direction of the resultant force experienced by the object follows the inclined plane.

If the object moves horizontally with the direction of the inclined plane (without sliding relative to each other), the direction of the resultant force to the object is horizontal.

If you look at the problem in combination with the whole and the part, first of all, it will generally not fly, so the direction of the resultant force it receives must be along the inclined plane, either up or down, and of course there are times when it is 0. There are just three possibilities, I believe you can get it, it may be that you have just started to contact this subject, and this part requires a little spatial perception, so you are a little confused, in fact, through practice, if you get used to it, everything will not be a problem.

Hope it helps.

1. When the object is in a state of stationary or uniform linear motion, the net force on the object is zero.

2. When the object accelerates or decelerates in a straight line along the inclined plane, the direction of the resultant force on the object is along the inclined plane (the same direction as the acceleration).

3. When the object is forced on the inclined plane to move in a circular motion (constant or variable speed), the direction of the resultant force of the object is perpendicular to the direction of the linear velocity (pointing to the center of the circle).

If the resultant force is horizontal, an external force is required, and if the inclined plane can move at a uniform speed on the horizontal plane, and the object is not moving relative to the inclined plane.

It is relatively simple along the inclined plane, as long as the object is not stationary when you put it on the inclined plane, and the inclined plane is stationary or moving at a uniform speed.

New to physics, right? When you first come into contact with new knowledge, there is a period of confusion!

Classmate, the question itself is a little problematic, you didn't say clearly the state of the inclined plane, and even you didn't say the state of the object, so your question can't be answered, but I can help you analyze it, I hope it can help you.

Then I assume that the inclined plane is fixed, 1: the force of the object when it remains at rest, only the object with a net force of 0 can maintain a state of rest or uniform motion (in the ideal state), the force on the object in the resting state has the direction of gravity vertically downward, the direction of the support force on the object is vertically inclined upward, and the static friction force on the inclined object is upward along the inclined surface, and the resultant force of these three forces is zero to keep the object at rest on the inclined plane! 2 The state of uniform linear motion is also the resultant force is zero, at this time the force is gravity, the inclined plane support force and the dynamic friction force and the direction of the kinetic friction force is opposite to the direction of velocity 3 The object is in a non-uniform linear motion state, at this time, if there is no external force, there will still be three kinds of force Gravity Support force Kinetic friction, the resultant force of the three should be consistent with the direction of motion of the object, that is, along the inclined plane If there is an external force, this situation will be more, so I will not analyze it!

At the beginning of studying physics, it is necessary to understand the force state of the object, so as to lay a solid foundation for future physics learning.

It depends on the state of motion of the object. If the external force is at rest, it is 0, and if it slides down, it will go down the inclined plane.

The formula for calculating the resultant force: 1. F-sum = f1+f2 [calculation of the resultant force of two forces in the same direction of the same straight line]; 2. F-Combination = F1-F2 [Calculation of the Resultant Force of Two Forces in the Opposite Direction of the Same Straight Line]. If there is an angle a between f1 and f2, the cosine theorem is used.

obtained, f-fit = (f12+f22-2f1f2cosa).

Extended Materials. What is resultant force.

If the effect is the same as that of a certain force f, then this force f is called the resultant force of several forces (equivalent method).

The direction of force f is the direction of the combined force of several forces.

Force is a vector quantity, and the resultant force refers to the vector sum of multiple forces acting on the same object together. The resultant force is a vector quantity, and the addition and subtraction of vectors satisfies the parallelogram rule.

and the law of triangles.

Decomposition of forces. <>

Finding the component of a known force is called the decomposition of the force.

1) The decomposition of a force is the inverse of the synthesis of a force, which also follows the parallelogram rule.

2) It is known that two divisions strive to have a unique solution for the resultant force, and to find the two components of a force, there are countless solutions if there are no constraints.

In order to obtain a definite solution to the only wild excavation, some conditions should be attached

1. The resultant force and the two components of the force are known. direction, the magnitude of the two components of force can be obtained.

Knowing the magnitude and direction of the resultant force and one component, the magnitude and direction of the nuclear spine resistance and the other component force can be obtained.

Knowing the resultant force, the magnitude of one component f1 and the direction of the other component f2, find the direction of f1 and the magnitude of f2:

If f1 = fsin0 or f1 f has a - group solution.

If f>f1 > fsin have two solutions.

3) In practical problems, they are generally decomposed according to the effect of force or the convenience of dealing with the problem.

Hello, dear. The formula for high school physical resultant force is f-sum 2=f1 2+f2 2+2f1*f2*cos The resultant force is nothing more than decomposing multiple forces into a straight line (when moving in a straight line), or two axes perpendicular to each other (all forces are in the same plane), or three spatial axes perpendicular to each other (the resultant force is in multiple planes), treating the object as a particle, and then adding and subtracting the vector to get the result. Dear, <>

The above is the answer I summarized for you, I am very happy to serve you, please give me a thumbs up, thank you very much for <>

I hope mine is helpful to you, and then I hope you are happy every day, have a good life<> and good luck always accompany you<>

First of all, let's talk about the meaning of these two propositions A is f1, f2, in the case of constant conditions, is it true that the larger the angle, the smaller the net force (the angle is 0-180 degrees). Consider f1 and f2 as two sides of a parallelogram, and the resultant force is the diagonal side, as shown in Figure 1

As the included angle increases, the shorter the diagonal, the smaller the resultant force. So A is right.

Proposition b, is the larger the angle and the greater the component force (the angle is 0-180 degrees) when the resultant force remains unchanged

When OC is the same, and the angle between them is 90 degrees, the component is uncertain, so it is not that the larger the angle, the greater the component.

For your question, if the force and the net force are not told to you to be the same, then the two propositions of a and b must be wrong, let me give you a counterexample, if at the beginning f1 = 1n, f2 = 1n, the angle is 0 and the net force is 2n

When the angle becomes 90 degrees, f1 = 100 n, f2 = 100n then the net force is 100 2n, it is obvious that the net force does not become smaller but larger. b The same is true for b, if the component and the resultant force do not tell you that they are constant, then there is no law to talk about.

The first one is definitely true.

Let the magnitude of the resultant force be f, then there is.

f 2 = f1 2 + f2 2 + 2 * f1 * f2 * cos(sita) is between sita=0-180 degrees, cos(sita) is a subtractive function, so the larger the sita, the larger the right side of the equation, i.e., f is larger.

Second, the problem is not clear, if a condition is attached, the magnitude of the two components is equal, i.e., f1=f2, then the above equation becomes.

f 2 = 2 * f1 2 * (1 + cos(sita)) so f1 2 = f 2 (2*(1+cos(sita))) when the sita changes between 0-180 degrees, the larger the sita, the smaller the cos(sita), and the smaller the denominator, so the larger the right side of the equation, that is, the greater the component. But if you don't say f1=f2, then it's pointless, because whether you say it's going to be smaller or bigger, I can come up with an f1 or f2 that makes it the opposite of what you say.

It is correct if the component force remains the same.

Try it with the sine theorem.

Half of the net force has an angle from 90 to 0

If the force is different, it would be nice to give a special example.

Force is a vector, that is, in addition to magnitude, there is also directionality, as shown in the figure, assuming that two common point forces f1 and f2 act on point o at the same time, if f1 is the x-axis of the rectangular coordinates, then f2 can be decomposed into a component oa along the f1 direction and ob along the f2 direction;

Because acting on the same point, the resultant force of the same direction is added along the original direction, so the component of the resultant force f of F1 and F2 along the X-axis direction oc=of1+ob, that is, the line segment f1c=ob;

Along the y-axis, the component of the resultant force f is cf=oa;

Obviously, in the right-angled triangle obf2 and f1cf, the corresponding angles are equal because the corresponding right-angled edges are equal and congruent, and of2 is parallel to f1f;

Thus, the quadrilateral of2ff1 is a parallelogram, of1 and of2 are the adjacent sides of the parallelogram, and of is the diagonal of the angle between the two sides.

Illustrate the resultant force of two common point forces, according to the parallelogram rule.

The angle between the two forces is obtuse.

and other cases).

FYI.