How to calculate the normal force

1.

Centripetal force formula:

extended data

generation of centripetal force:

because circular motion belongs to curvilinear motion, objects in circular motion will also be affected by external forces different from their velocity directions. For the object in circular motion, the centripetal force is a kind of pulling force, and its direction changes constantly with the movement of the object in the circular orbit. This pulling force points to the center of the circle along the radius of the circle, so it is called "centripetal force"

the centripetal force points to the center of the circle, and the object controlled by the centripetal force moves along the tangent direction, so the centripetal force must be perpendicular to the motion direction of the controlled object, and only proces the acceleration in the direction of the velocity normal

Therefore, the centripetal force only changes the direction of motion of the controlled object, but does not change the speed of motion, even in non-uniform circular motion. In the non-uniform circular motion, the tangential acceleration changing the velocity is not caused by the centripetal force

2.

1. Gravity g = mg

(vertically downward, g = 9.8m/s2 ≈ 10m / S2, the action point is at the center of gravity, applicable to the earth surface)

2. Hooke's law f = KX

{along the recovery deformation direction, K: stiffness coefficient (n / M), X: deformation variable (m)}

3. Sliding friction force F = μ FN

{opposite to the relative motion direction of the object, μ： Friction coefficient, FN: positive pressure (n)}

{rrrrrrr}

extended data:

different classification of force

1. According to the nature of force, it can be divided into gravity, universal gravitation, elastic force, friction force, molecular force, electromagnetic force, nuclear force, etc Note that gravity is not equal to gravity under all conditions Gravity does not point to the center of the earth under all conditions. Gravity is a component of the earth's gravitational force on an object, and the other component is a centripetal force. Only on the equator does gravity point to the center of the earth.)

According to the effect of force, it can be divided into tension, tension, pressure, supporting force, power, resistance, centripetal force, restoring force, etc

According to the research object, it can be divided into external force and internal force

According to the action mode of force, it can be divided into non-contact force (such as gravitation, electromagnetic force, etc.) and contact force (such as elastic force, friction force, etc.)

There are four basic interactions (forces): gravitational interaction, electromagnetic interaction, strong interaction and weak interaction

nature of force:

materiality: force is the effect of an object (matter, mass) on an object (matter, mass). When an object is subjected to a force, another object must exert this effect on it. Force cannot exist independently without an object

interactivity (interaction): the interaction between any two objects is always mutual, and the object exerting the force must also be the object under the force. As long as one body exerts a force on another, the stressed body in turn will surely add a force to the exerted body Generating conditions: the force is equal in size (the resultant force is zero, in a state of non directional static motion) or not equal, in the opposite direction, acting on two different objects, and acting on the same straight line. It can be summarized as: foreign body, equivalent, reverse, collinear. A pair of interaction forces must proce and disappear at the same time.)

Vectoriality: force is a vector, which has both magnitude and direction

simultaneity: the force proced and disappeared at the same time

independence: the effect of one force does not affect the effect of another

includes three elements: the size, direction and action point of the force. The accurate expression of the three elements of force by a directed line segment is called the diagram of force. The size is represented by the length of a scaled line segment, the direction is represented by an arrow, the point of action is represented by an arrow or the tail of an arrow, and the straight line along which the direction of a force follows is called the line of action of a force. The diagram of the force is used for the calculation of the force. When the judgment power is large, we must pay attention to the scale of the line segment, because even if one line segment is longer than another line segment, but the scale of the long line segment is also longer, the force represented by the short line segment is not necessarily smaller than that represented by the long line segment

3. When the object moves in a circle, the normal force is the centripetal force
when the object moves in a general curve, the normal force is perpendicular to the speed direction and points to the inside of the curve

4. Different, the supporting force should be included in the range of normal force, because the supporting force only appears when there is a contact surface, which is a concept. But in circular motion, sometimes there is no contact surface. At this time, there is only normal force (along the direction of the circle), no supporting force!

5. In short, the normal force is applied in the direction perpendicular to the direction of motion.

6. Not exactly, because centripetal force is not force
the force received by an object moving in a circle can be decomposed into normal (pointing to the center of the circle) and tangential. The normal force provides the centripetal force needed for the object to move in a circle. It changes the direction of the velocity, while the tangential force changes the velocity of the object.

7.

Centripetal force formula:

in the circular motion, the forces on the object are orthogonal decomposed in the tangential and normal directions, and the resultant force in the normal direction is equal to the centripetal force

W = V square / R square, f = MRW square = MV square / R

The rotational speed is less than P > V, v = circumference / T period, f = MV square / r = 4 Pai square, Mr / T square

So w is the acceleration and t is the period

extended data:

circular motion can be divided into uniform circular motion and non-uniform circular motion according to whether the velocity changes

for an object moving in a circular motion with uniform velocity, the velocity is constant, but the direction changes, so the acceleration always points to the center of the circle, and its size remains unchanged; The external force always points to the center of the circle, and its size remains unchanged

the velocity direction and size of an object in non-uniform circular motion change. Besides the acceleration pointing to the center of the circle, it also has the acceleration along the tangent direction, so the resultant acceleration does not point to the center of the circle, and the resultant force does not point to the center of the circle. The centripetal acceleration of the object a = V & # 178/ R varies with V, and centripetal force a varies with F = ma

when the ball passes through point a from top to bottom, it is affected by two forces. The gravity g direction is the same as VA, which changes the ball's speed. The orbital elastic force n is perpendicular to VA and points to the center of the circle, which changes the ball's speed direction. That is to say, it provides the centripetal force for the ball to make a circular motion. The resultant force F and VA form an angle, but does not point to the center of the circle

8. Force is the reason to change the state of motion
the force in the same direction of motion accelerates the object; The force opposite to the direction of motion slows the object down
in other words, the force on the same line with the direction of motion changes the "size" of the object's speed
the force "perpendicular" to the direction of motion can not change the speed, only the direction of speed
the acceleration in the question is caused by the force. Force is the cause, acceleration is the result