"Centripetal Acceleration" Circular Motion PPT Excellent Courseware

Description

"Centripetal Acceleration" Circular Motion PPT Excellent Courseware

Part One: Learning Objectives

1. Understand the concept of centripetal acceleration.

2. Know the relationship between centripetal acceleration, linear velocity and angular velocity.

3. Be able to use the centripetal acceleration formula to solve related problems.

Centripetal acceleration PPT, part 2 content: 01 sort out the teaching materials and lay a solid foundation

The direction of acceleration of uniform circular motion

1. Definition: When an object moves in a uniform circular motion, its acceleration always points toward ________. This acceleration is called centripetal acceleration.

2. The role of centripetal acceleration: The direction of centripetal acceleration is always _________ with the direction of speed, so centripetal acceleration only changes the ________ of the speed, but does not change the ________ of the speed.

The acceleration of uniform circular motion

1. Centripetal acceleration formula

an＝_____ or an＝_____.

2. The formula of centripetal acceleration applies to both uniform circular motion and non-uniform circular motion.

Ready to use

1. Decide whether the following statements are true or false.

(1) The acceleration of an object in uniform circular motion must not be 0.()

(2) The acceleration of uniform circular motion always remains unchanged. ()

(3) Uniform circular motion is uniformly accelerated motion.

(4) The direction of centripetal acceleration of uniform circular motion points to the center of the circle at all times, and its magnitude does not change. ()

(5) According to an=___, we know that the centripetal acceleration an is inversely proportional to the radius r. ()

(6) According to an=ω2r, the centripetal acceleration an is proportional to the radius r. ()

2. A small ball is tied to one end of a 0.2 m long string, and the other end of the string is fixed on a horizontal table, so that the ball makes uniform circular motion on the table with a linear speed of 0.6 m/s, then the ball The angular velocity of motion is _______, and the centripetal acceleration is ________.

Centripetal acceleration PPT, the third part of the content: 02 Exploring key points to improve literacy

Centripetal acceleration and its direction

guided inquiry

As shown in Figure 1A, the earth moves in a uniform circular motion around the sun (approximately); as shown in Figure B, a small ball on a smooth tabletop moves in a uniform circular motion around the thumbtacks on the tabletop under the traction of a thin line.

(1) Analyze the forces on the earth and the ball, and explain the acceleration directions of the earth and the ball;

Answer: The earth is only affected by the gravity of the sun, and the direction points to the center of the circle, and the direction of acceleration points to the center of the circle. The small ball is affected by gravity, supporting force, and pulling force, and the resultant force points to the center of the circle, so the direction of acceleration points to the center of the circle.

(2) What is the role of the acceleration of the earth and the ball?

Answer: Since the direction of acceleration points to the center of the circle, acceleration only changes the direction of the velocity, not the magnitude of the velocity.

(3) Do the acceleration directions of the earth and the ball change? What kind of motion is uniform circular motion?

Answer: Since the acceleration of the earth and the ball always points toward the center of the circle along the radius, the direction of acceleration changes. Uniform circular motion is a variable acceleration curve motion.

knowledge deepening

Understanding centripetal acceleration and its direction

1. The direction of centripetal acceleration: always points to the center of the circle, and the direction changes all the time.

2. The role of centripetal acceleration: The direction of centripetal acceleration is always perpendicular to the direction of velocity, so centripetal acceleration only changes the direction of velocity, not the magnitude of velocity.

3. Properties of circular motion: Regardless of whether the centripetal acceleration an changes in magnitude, its direction changes all the time, so the acceleration of the circular motion changes all the time, and the circular motion is a variable acceleration curve motion.

4. The acceleration of variable-speed circular motion does not point to the center of the circle. This acceleration has two components: one is centripetal acceleration, and the other is tangential acceleration. Centripetal acceleration describes the speed of change in speed direction, and tangential acceleration describes the speed of change in speed. , so in variable-speed circular motion, the direction of centripetal acceleration always points to the center of the circle.

Example 1 Which of the following statements about centripetal acceleration is correct?

A. Centripetal acceleration indicates how quickly the velocity of an object in circular motion changes.

B. The direction of centripetal acceleration does not necessarily point to the center of the circle.

C. Centripetal acceleration describes the speed of change in the direction of linear velocity.

D. The centripetal acceleration of uniform circular motion remains unchanged.

The magnitude of centripetal acceleration

1. Centripetal acceleration formula

2. Applicable scope of the centripetal acceleration formula

The centripetal acceleration formula is not only applicable to uniform circular motion, but also to non-uniform circular motion. v is the linear velocity at that position, and whether the object is doing uniform circular motion or non-uniform circular motion, the direction of its centripetal acceleration All point to the center of the circle.

3. The relationship between centripetal acceleration and radius (shown in Figure 2)

Example 2 As shown in Figure 3, a sphere rotates uniformly around the axis O1O2 at an angular velocity ω. A and B are two points on the surface of the sphere. Which of the following statements is correct?

A. Two points A and B have the same angular velocity

B. Two points A and B have the same linear speed.

C. The directions of centripetal acceleration at points A and B both point to the center of the sphere.

D. The ratio of the centripetal accelerations at points A and B is 2:1

Example 3 (2019 Datong Interim) In the belt transmission device shown in Figure 4, the shaft of wheel A and the shafts of wheels B and C are both horizontal axes. Among them, the radii of wheels A and C are equal, and the radius of wheel B is is half of the radius of wheel C. The three points A, B, and C are the points on the edges of wheels A, B, and C respectively. If the belt does not slip during transmission, then

A.The ratio of the linear velocities of two points A and B is 2:1

B. The ratio of the angular velocities of two points B and C is 1:2

C. The ratio of the centripetal accelerations at points A and B is 2:1

D. The ratio of the centripetal accelerations at points A and C is 1:4

Method summary

Application skills of centripetal acceleration formula

Each formula of centripetal acceleration involves the changing relationship of three physical quantities, and the relationship between the other two physical quantities must be analyzed when one physical quantity remains unchanged.

(1) First determine whether the linear velocities of each point are equal or the angular velocities are the same.

(2) When the linear velocities are equal, the centripetal acceleration is inversely proportional to the radius. When the angular velocities are the same, the centripetal acceleration is directly proportional to the radius.

Centripetal acceleration PPT, the fourth part: 03 in-class drill, implementation point by point

1. (Understanding of the centripetal acceleration formula) Regarding the particle moving in a uniform circular motion, which of the following statements is correct?

A. From an= we can see that an is inversely proportional to r

B. It can be seen from an=ω2r that an is proportional to r

C. It can be seen from v=ωr that ω is inversely proportional to r

D. It can be seen from ω=2πf that ω is proportional to f

2. (Understanding of the centripetal acceleration formula) (Multiple choice) (End of the first semester of Changfeng No. 2 Middle School and Senior High School in 2019) Both objects A and B are doing uniform circular motion. In the following cases, which statement about centripetal acceleration is correct?

A. When their angular velocities are equal, B's linear velocity is smaller, and B's centripetal acceleration is smaller.

B. When their periods are equal, the larger the radius of A, the larger the centripetal acceleration of A.

C. When their linear velocities are equal, the radius of B is smaller, and the centripetal acceleration of B is smaller.

D. When their linear velocities are equal, the angle connected by A and the center of the circle is larger than that of B in the same time, then the centripetal acceleration of A is smaller than that of B.

3. (Calculation of Centripetal Acceleration) (2019·Shandong Province Experimental Middle School Midterm) There are three gears A, B, and C in a gearbox, as shown in Figure 6. Their radii are r1, r2, and r3 respectively. If The angular velocity of wheel A rotating at a constant speed is ω, and the three wheels do not slip against each other, then the centripetal acceleration of each point on the edge of wheel C is

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For more information about the "Circular Motion Centripetal Acceleration" PPT courseware, please click on the Circular Motion PPT Centripetal Acceleration PPT tag.

"Centripetal Acceleration" Circular Motion PPT high-quality courseware:

"Centripetal Acceleration" Circular Motion PPT High-quality Courseware Part One: Core Competency Objectives Physical Concepts Centripetal acceleration and its direction, the relationship between centripetal acceleration and linear velocity, and the relationship between centripetal acceleration and angular velocity. Scientific thinking Able to use centripetal acceleration..

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"Centripetal Acceleration" Circular Motion PPT Courseware Part One Content: Foundation for Necessary Knowledge Literacy [Thinking] When a ball makes uniform circular motion around one end of a rope, what is the direction of its acceleration? How to calculate its size? Does its speed change? Tips: The direction of acceleration refers to...

"Centripetal Acceleration" Circular Motion PPT:

"Centripetal Acceleration" Circular Motion PPT Part One Content: Learning Objectives 1. Know that uniform circular motion is a variable-speed motion, with acceleration pointing toward the center of the circle. Centripetal acceleration. 2. Know the expression of centripetal acceleration and be able to choose the appropriate centripetal acceleration according to the problem situation..

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Update Time: 2024-06-08

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