"Particle and Displacement" Description of Motion PPT Download

Description

"Particle and Displacement" Description of Motion PPT Download

Part 1: Essential knowledge and foundation of literacy

1. Sephiroth

1. Ideal model method: a method that highlights the _____________ of the problem, ignores the _____________, and simplifies the problem.

2. Conditions for an object to be regarded as a particle:

3. The connotation of mass point: a point with _________ used to replace an object.

4. The relationship between the particle and the object: The particle _________ a real object, which is a physical model of ___________.

2. Displacement and distance

1. Displacement:

(1) Physical meaning: describes the _____________ of an object.

(2) Size: _________ of the directed line segment from the initial position to the final position.

(3) Direction: The direction of the arrow pointing from ___________ to ___________.

2. Scalar and vector:

(1) Scalar: There are only physical quantities that are ________ but not ________.

(2) Vector: A physical quantity that contains both ________ and ________.

3.Distance:

(1) Physical meaning: describes the length of the object’s movement trajectory.

(2)Connotation: _________ of the movement trajectory of an object.

4. The difference between displacement and distance:

The correct statements about displacement and distance are _________.

①The distance is the length of the actual trajectory and has no direction.

②A student ran a circle on the playground for 2 minutes, but his displacement was zero.

③Displacement and distance are both directional physical quantities.

④The displacement of 3 m is larger than the displacement of -5 m.

3. Displacement-time image (s-t image)

1. Image establishment: In the plane rectangular coordinate system, the horizontal axis represents ________ and the vertical axis represents ________.

2. The s-t image of uniform linear motion is an inclined _________.

PPT on particle and displacement, part 2: key abilities and literacy formation

1. Mass point model

1. Idealized method:

(1) The mass point is a scientific abstraction and an idealized physical model. When studying the movement of objects, it is an approximation of the actual object by grasping the main factors and ignoring the secondary factors.

(2) In physics, it is a commonly used scientific research method to highlight the main factors of the problem, ignore the secondary factors, establish an idealized "physical model" through the abstraction of things, and use it as the research object.

2. Three characteristics of particle:

(1) No size or shape.

(2) Has the entire mass of the object.

(3) is an idealized physical model and does not exist in real life.

3. Conditions for treating an object as a particle: When the size and shape of the object have a negligible impact on the research problem, the object can be regarded as a particle regardless of its size.

【Think·Discussion】

Situation: As shown in the picture, an international marathon is in progress.

Discussion: (1) When a coach studies the impact of a marathon runner's arm swing and stride length on speed, can the coach regard him as a "point"? (Model construction)

Tip: No. When studying the impact of an athlete's arm swing and stride length on speed, if his size and movements have an impact on the research problem, they cannot be regarded as mass points.

(2) When studying the speed changes of an athlete throughout the entire process, can he be regarded as a "point"? (scientific thinking)

Tip: Yes. When studying the speed changes of an athlete throughout the process, if his size and movement have no impact on the research problem, it can be regarded as a mass point.

[Typical example demonstration]

(Multiple choice) (2019·Fuzhou Senior High School Test) Which of the following statements is correct ()

A. When studying the time it takes for an airplane to fly from Chengdu to Beijing, the airplane can be regarded as a particle

B. When studying the rotation of helicopter propellers, the helicopter can be regarded as a particle

C. When studying the time it takes for a train to cross the Yangtze River Bridge, the train can be regarded as a particle

D. When studying the time it takes for a car to cross the Yangtze River Bridge, the car can be regarded as a particle

[Analysis] Choose A or D. The size of the aircraft in A has no impact on the problem studied, so it can be regarded as a mass point; the helicopter propeller in B is part of the helicopter, and the size of the helicopter cannot be ignored, so the helicopter cannot be regarded as a mass point; when the train crosses the bridge in C, The length of the train will affect the time it takes for the train to cross the bridge, so the train cannot be regarded as a particle; when the car crosses the bridge in D, the length of the car is much smaller than the length of the bridge, and the length of the car has very little impact on the time it takes the car to cross the bridge, so A car can be considered a particle.

[regular method]

The idea of ​​​​judging whether an object can be regarded as a particle

(1) Determine the nature of the research problem, that is, what are the elements of concern in the problem and what are the physical quantities to be analyzed and solved.

(2) Assume that the shape and size of the object are ignored, and consider whether the physical quantities to be solved and the elements of concern are affected.

(3) If the physical quantity to be solved is not affected, the object can be regarded as a particle; if it is affected, the object cannot be regarded as a particle.

【Literacy Training】

1. (2019·Nanping High School Grade 1 Test) The following statement about the particle is correct ()

A. All light and small objects can be regarded as particles.

B. Only objects with very small volumes can be regarded as particles

C. The particle is an idealized model and does not actually exist. Therefore, introducing this concept does not make much sense.

D. If the shape and size of the object are irrelevant or secondary factors to the problem being studied, the object can be regarded as a particle

2. Among the following Olympic events, the research object can be regarded as a mass point ()

A. When studying the rotation of the support pole in the athlete's hand while supporting the ground in the pole vault competition

B. When determining a marathon runner’s position in the race

C. When studying the movements of athletes in Taekwondo competitions

D. When studying the rotation of table tennis balls in table tennis competitions

2. The difference and connection between displacement and distance

1. Judgment of vectors and scalars:

(1) Representation of vector:

①Illustration of a vector: It is represented by a line segment with an arrow. The length of the line segment represents the magnitude of the vector, and the direction of the arrow represents the direction of the vector.

②Vectors on the same straight line: You can first establish a straight-line coordinate system, and add a positive or negative sign in front of the value to indicate the direction of the vector. The positive sign indicates the same as the positive direction specified by the coordinate system, and the negative sign indicates the opposite direction to the specified positive direction.

2. Comparison of displacement and distance:

the difference

Describing the position change of the particle, it is a directed line segment from the initial position to the final position.

Describes the length of the actual trajectory of the particle

is a vector. The direction from the starting position to the ending position is the direction of displacement. The length of this vector segment is the magnitude of the displacement.

It is a scalar quantity, with only size and no direction. The length of the object’s trajectory is the size of the distance.

connect

(1) They are all physical quantities that describe the spatial characteristics of particle motion;

(2) They are all process quantities;

(3) During a movement, the magnitude of the displacement is not greater than the corresponding distance. Only when the particle moves in a one-way straight line, the magnitude of the displacement is equal to the distance.

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For more information about the "Description of Motion PPT PPT and Displacement" PPT courseware, please click the PPT PPT Description of Motion PPT tag.

"Particle and Displacement" PPT courseware describing motion:

"Particle and Displacement" Description of Motion PPT Courseware Part One Content: Course Standard Requirements 1. Understand the concept of mass point and know the conditions under which an object can be regarded as a mass point. 2. Understand the concept of displacement and know the difference between displacement and distance. 3. Know what vectors, scalars and...

"Particle and Displacement" Description of Motion PPT:

"Particle and Displacement" Description of Motion PPT Part One: Learning Objectives 1. Understand the concept of particle and the conditions under which an object can be regarded as a particle. 2. Understand the concept of displacement and know the difference and connection between displacement and distance. 3. Know vectors and scalars, and be able to distinguish between vectors..

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Update Time: 2024-11-18

This template belongs to Physics courseware Lu Ke Edition High School Physics Compulsory Course One industry PPT template

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