Although physics is not the main course for liberal arts students, it still needs to be tested. So what are the knowledge points of physics in the exam? Let me share with you the knowledge points of the liberal arts physics exam. Welcome to reading.

Knowledge points of liberal arts physics examination Chapter 65438 +0: force 1. Force: Force is the interaction between objects.

1, and the international unit of force is Newton, which is represented by n;

2. Diagram of force: The directed line segment with arrow indicates the magnitude, direction and action point of force;

3. Schematic diagram of force: the direction of force is indicated by line segments with arrows;

4. Forces can be divided into gravity, elasticity, friction, molecular force, electric field force, magnetic field force, nuclear force and so on.

1 gravity: the force exerted on an object due to the gravity of the earth;

A gravity is not gravity, but a component of gravity;

The direction of gravity is always vertical downward, vertical to the horizontal plane downward.

The instrument for measuring gravity is a spring scale;

D the center of gravity is the equivalent point of each part of an object under the action of gravity, and only the center of gravity of an object with regular geometric shape and uniform mass distribution is its geometric center;

Elastic force: the force exerted by a deformed object on an object in contact with it in order to restore its deformation;

A conditions for producing elastic force: two objects contact and deform; The deformation of the applied object generates elastic force;

B Elasticity includes: supporting force, pressure, thrust, tension, etc.

C the direction of supporting force and pressure is always perpendicular to the contact surface, pointing to the supported or pressed object; The direction of tension is always along the contraction direction of the rope;

D within the elastic limit, the elastic force is proportional to the shape variable; F=Kx

3 Friction: When two objects in contact with each other have relative motion or a tendency of relative motion, the force that hinders the relative motion of the objects is called friction;

A conditions for generating friction: object contact, rough surface, extrusion, relative motion or relative motion trend; Elastic force does not necessarily have friction, but there must be elastic force between two things with friction;

B. The direction of friction is opposite to the relative motion or relative motion trend of the object;

C sliding friction f sliding =μFN pressure is not necessarily equal to the gravity of the object;

D the magnitude of static friction is equal to the external force that makes objects move relatively;

4 resultant force and component: if several forces have the same effect on an object as a force, this force is called the resultant force of those forces, and those forces are called the component of this force;

The resultant force and the component force have the same effect;

B. The resultant force and component force follow the parallelogram law: if two line segments representing forces are used as adjacent sides to form a parallelogram, the diagonal line sandwiched between these two sides represents the resultant force of the two forces;

C the resultant force is greater than or equal to the difference between the two components and less than or equal to the sum of the two components;

D when the force is decomposed, the force is usually decomposed according to its function; Or decompose the force along the moving direction or trend of the object and its vertical direction; Orthogonal decomposition method of force;

Second, vector: a physical quantity with both size and direction.

Such as force, displacement, velocity, acceleration, momentum and impulse.

Scalar: Physical forces with only magnitude and no direction, such as time, speed, work, power, distance, current, magnetic flux and energy.

Third, the condition that the object is in a state of equilibrium, static and uniform linear motion: the resultant force on the object is equal to zero;

1. If an object is in equilibrium under the action of three * * * point forces, the resultant force of any two forces is equal to the third force;

2. When an object is in an' equilibrium' state under the action of n * * * point forces, the resultant directions of any nth force and N- 1 force are opposite and equal;

3. The resultant force of an object in equilibrium in any two mutually perpendicular directions is zero;

Knowledge points of liberal arts physics examination Chapter 2: Linear motion 1. Mechanical motion: the position change of an object relative to other objects is called mechanical motion;

1, reference system: an object assumed to be stationary for studying its motion; Also known as reference objects, reference objects are not necessarily static;

2. Particle: an object that only considers the mass of the object without considering its size and shape;

1 particle is an idealized model;

2. Conditions for an object to be regarded as a particle: the shape and size of the object are too small to count;

For example, study the movement of the earth around the sun, and the train goes from Beijing to Shanghai;

3. Time and time interval: on the axis representing time, time is a point and time interval is a line segment;

For example, 5 o'clock sharp, 9 o'clock and 7: 30 are moments, and 45 minutes and 3 hours are time intervals;

4. Displacement: the phase line segment from the starting point to the end point, and the displacement is a vector, which is represented by the phase line segment; Distance: a curve describing the trajectory of particles;

1 The displacement is zero, and the distance is not necessarily zero; The distance is zero and the displacement must be zero;

Only when the particle moves in a unidirectional straight line, the displacement of the particle is equal to the distance;

The international unit of displacement is meter, which is expressed by m.

5. Displacement time image: establish a rectangular coordinate system, with the horizontal axis representing time and the vertical axis representing displacement;

The displacement image of 1 with uniform linear motion is a straight line parallel to the horizontal axis;

2. The displacement image of uniform linear motion is an inclined straight line;

The tangent value of the included angle between the displacement image and the horizontal axis indicates the speed; The greater the included angle, the greater the speed;

6. Speed is a physical quantity indicating the speed of particle movement;

1 The speed of an object at a certain moment is faster than the instantaneous speed; The speed of an object in a certain time is called the average speed;

2. Speed only indicates the size of speed, which is a scalar;

7. Acceleration: it is a physical quantity that describes the speed change of an object;

1 definition of acceleration: a = vt-v0/t.

The magnitude of acceleration has nothing to do with the speed of the object;

3. When the speed is high, the acceleration is not necessarily large; The speed is zero, and the acceleration is not necessarily zero; The acceleration is zero, and the speed is not necessarily zero;

4 The speed change is equal to the terminal speed minus the initial speed. Acceleration is equal to the ratio of speed change to time spent. The change rate of speed has nothing to do with the number of speed changes.

5 acceleration is a vector, and the direction of acceleration is the same as the direction of speed change;

The international unit of acceleration is m/s2.

Second, the law of uniform linear motion:

1, speed: the relationship between speed and time in uniform linear motion: vt=v0+at.

Note: Generally, we take the direction of initial velocity as the positive direction, so when the object accelerates, A takes a positive value, and when the object decelerates, A takes a negative value;

1 The instantaneous speed of an object moving in a straight line at a uniform speed is equal to the average of the initial speed and the final speed;

2. The instantaneous speed of a uniformly changing object in the middle moment is equal to the average speed, which is equal to the average of the initial speed and the final speed;

2. Displacement: the relationship between displacement and time of uniform linear motion: s=v0t+ 1/2at.

Note: A takes a positive value when the object accelerates and a negative value when the object decelerates;

3. Inference: 2as=vt2-v02

4. The displacement difference of an object moving in a straight line at a uniform speed in two consecutive equal time intervals is equal to colonization; s2-s 1=aT2

5. Uniformly accelerated linear motion with zero initial velocity: the first 1 second, the second second, the relationship between displacement and time is: the ratio of displacement is equal to the square ratio of time; The relationship between displacement and time at 1 and the second second is that the ratio of displacement is equal to the odd ratio.

3. Free-falling motion: the motion of an object falling from a height only under the action of gravity;

1, displacement formula: h= 1/2gt2.

2. Speed formula: vt=gt

3. Inference: 2gh=vt2

Chapter 3: Newton's law 1. Newton's first law of inertia: all objects always keep moving in a straight line at a uniform speed or at rest until an external force forces them to change this behavior.

1, only when the external force acting on the object is zero can the object be in a state of static or uniform linear motion;

2. Force is the reason for changing the speed of an object;

3. Force is the reason to change the motion state of an object. If the speed of an object is constant, its motion state will remain unchanged.

4. Force is the cause of acceleration;

2. Inertia: The property that an object maintains a uniform linear motion or a static state is called inertia.

1, all objects have inertia;

2. The size of inertia is only determined by the mass of the object;

3. Inertia is a physical quantity that describes the difficulty of changing the motion state of an object;

Third, Newton's second law: the acceleration of an object is directly proportional to the applied external force and inversely proportional to the mass of the object, and the direction of acceleration is the same as that of the applied external force.

1, mathematical expression: a = f/m;

2. The acceleration changes and disappears with the change of force.

3. When the force direction of the object is consistent with the motion direction, the object accelerates; When an object is forced in the opposite direction to its motion, it will slow down.

4. Definition of Newton as the unit of force: the force that causes an object with a mass of 1kg to produce an acceleration of 1m/s2 is called1n;

Fourth, Newton's third law: the acting force and reaction force between objects are always equal in size and opposite in direction, and act on the same straight line;

1, the acting force and reaction force are generated, changed and disappeared at the same time;

2. The fundamental difference between acting force and reaction force and balance force is that acting force and reaction force act on two interacting objects, and balance force acts on the same object.

Knowledge points of liberal arts physics examination Chapter IV Curve motion and the law of universal gravitation

1. Curve motion: the trajectory of a particle is the motion of a curve;

1, the direction of velocity changes at any moment in the curve motion, and the velocity direction of a particle at a certain point or moment is the tangent direction of the curve at that point.

2. Conditions for a particle to move in a curve: the direction of the external force applied to the particle is not on the same straight line with its moving direction, and the trajectory deflects to its stress direction.

3, the characteristics of curvilinear motion:

4. Curved motion must be variable speed motion;

5. The resultant acceleration of curvilinear motion is not in a straight line with its velocity direction;

6, the role of force:

1 When the direction of force is consistent with the direction of motion, the force changes speed;

2. When the direction of force is perpendicular to the direction of motion, the force changes the direction of speed;

3. When the direction of the force is neither vertical nor parallel to the speed direction, the force changes both the magnitude and direction of the speed;

Second, the synthesis and decomposition of motion:

1, the method of judging and moving: the actual movement of an object is a combined movement.

2. Synchronism of joint movement and sub-movement: The time spent by joint movement and sub-movement is always equal;

3. The combined displacement and sub-displacement, combined velocity and sub-velocity, acceleration and sub-acceleration all follow the parallelogram law;

3. Flat throwing motion: The horizontal throwing motion of an object under the action of gravity is called flat throwing motion;

1, the essence of flat throwing motion: the object moves in a straight line at a uniform speed in the horizontal direction and falls freely in the vertical direction;

2. Horizontal uniform linear motion and vertical free-falling motion are isochronous;

3. Solution: Study the bisection motion in horizontal direction and vertical direction respectively, and sum the motions with parallelogram rule;

4. Uniform circular motion: particles move along a circle. If the arcs passing through in any equal time are equal, this motion is called uniform circular motion;

1, the linear velocity is equal to the arc length divided by the time: v=s/t, and the linear velocity direction is the tangent direction of the point;

2. Angular velocity is equal to the angle of particle rotation divided by the time taken: ω = φ/t.

3. The relationship between angular velocity, linear velocity, period and frequency:

1v = 2πr/T； 2ω= 2π/T； 3V =ωr； 4、f = 1/T；

4, centripetal force:

1 Definition: The force exerted on the center of the circle by an object moving in a uniform circle along the radius is called centripetal force.

2 direction: always pointing to the center of the circle, perpendicular to the speed direction.

3 Features: ① Only change the speed direction, without changing the speed; (2) named according to the effect.

4 calculation formula: direction f =mv2/r=mω2r.

5. centripetal acceleration: Direction A = V/R = ω R

Five, Kepler's three laws:

1, Kepler's first law: the orbits of all planets around the sun are ellipses, and the sun is at a focus of all ellipses;

Note: in middle school, unless otherwise specified, the trajectory of the planet is generally regarded as a circle;

2. Kepler's third law: all planets and the sun line sweep the same area at the same time;

3. Kepler's third law: the ratio of the cube of the semi-long axis of all planets to the square of period of revolution is equal; Formula: R3/T2 = K；;

Explanation: 1R represents the semi-long axis of the orbit, t represents period of revolution, and k is a constant, and its size is related to the sun;

② When the trajectory of the planet is regarded as a circle, R represents the expected radius;

This formula also applies to other celestial bodies, such as satellites orbiting the earth;

6. Law of Universal Gravitation: Any two objects in nature attract each other, and the magnitude of gravity is directly proportional to the mass of these two objects and inversely proportional to the square of their distance.

1, calculation formula: F=GMm/r2.

2. Ideas to solve the problem of celestial motion:

1 applied gravity equals centripetal force; The linear velocity and period formulas of uniform circular motion are applied;

The gravitational force of an object acting on the earth's surface is equal to gravity; 3 If density is required, use m = ρ v, and v = 4 π R3/3.

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