"Inference of Uniformly Variable Speed ​​Linear Motion" Research on Uniformly Variable Speed ​​Linear Motion PPT

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"Inference of Uniformly Variable Speed ​​Linear Motion" Research on Uniformly Variable Speed ​​Linear Motion PPT

High-frequency test point 1: Understanding and application of the average speed formula

[Knowledge Comprehensive]

1. The average speed formula: v=vt2=v0+v2, that is, the average speed of an object moving in a straight line at a uniform speed within any period of time t is equal to the instantaneous speed at the middle moment of this period of time, and is also equal to the velocity vector at the beginning and end of this period of time. and half.

2. Derivation: Suppose the initial velocity of an object making uniform linear motion is v0, the acceleration is a, and the velocity at time t is v.

From x=v0t+12at2, the average speed v=xt=v0+12at ①

From v=v0+at, when t′=t2, v=v0+a·t2 ②

From ①② we get v=v and v=v +a·t2 ③

Solve from ②③ to get v = v0 + v2

To sum up, v=v=v0+v2.

[Training Unicom]

Typical example 1 It lasted 20 s and moved 50 m. Find the maximum speed of the car during the above motion.

[Instant training]

1. September 18, 2018 is the "anniversary of the September 18th Incident". China's J-20 stealth fighter conducted "four aircraft in the same frame" flight training. Assume that the fighter starts from rest and performs a uniformly accelerated linear motion before taking off. The time required to reach the take-off speed v is t, then the distance traveled before taking off is ()

A. vtB.vt2

C. 2vt D. Can not be sure

2. A particle moves in a straight line at a uniform speed through three points A, B, and C on the straight line. It is known that AB = BC = 4 m. The average speed of the particle moving between AB is 6 m/s, and the average speed moving between BC is 6 m/s. is 3 m/s, then the acceleration of the particle is ()

A. 1.5 m/s2 B． 4m/s2

C. 3 m/s2 D． -2m/s2

3． An object moves in a straight line, and its vt image is as shown in the figure, then the average speed of the object within 0 to t1 ()

A. Equal to v0＋v12

B. Greater than v0＋v12

C. Less than v0＋v12

D. Insufficient conditions for comparison

High-frequency test point 2: Understanding and application of the instantaneous speed formula at the midpoint position

1. The instantaneous speed formula of the midpoint position: v = v02 + v22, that is, in uniform linear motion, the instantaneous speed of the midpoint position of a certain segment of displacement is equal to the "square, mean, and root" values ​​of the initial and final velocity of this segment of displacement.

2. Derivation: As shown in the figure, the displacement of the previous section is v 2 - v02 = 2a • x2, and the displacement of the subsequent section is v2 - v 2 = 2a • x2, so v 2 = 12 • (v02 + v2), that is, v = 12v02 + v2.

[Training Unicom]

Typical Example 2 , the midpoint speed of AB time is v4, and the average speed of the whole journey is v5, then which of the following conclusions is correct?

A. The velocity of the object passing through the midpoint of AB displacement is v1+v22

B. The velocity of the object passing through the midpoint of AB displacement is v12+v222

C. If it is a linear motion with uniform deceleration, then v3

D. In uniform linear motion, there must be v3>v4=v5

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For more information about the PPT courseware "Research on Linear Motion at Uniform Speed ​​and Inference of Linear Motion at Uniform Speed", please click on the Research on Linear Motion at Uniform Speed ​​PPT. Inference of Linear Motion at Uniform Speed ​​PPT tag.

"Inference of Uniformly Variable Speed ​​Linear Motion (2)" Research on Uniformly Variable Speed ​​Linear Motion PPT:

"Inference of Uniformly Variable Speed ​​Linear Motion (2)" Research on Uniformly Variable Speed ​​Linear Motion PPT Part One Content: Basic Review Speed ​​formula v=v0+at, when v0=0, v=at Displacement formula x=v0t+12at2, when v0=0 ,x＝12at2 v2－v20＝2ax,..

"Inference of Uniformly Variable Speed ​​Linear Motion (1)" Research on Uniformly Variable Speed ​​Linear Motion PPT:

"Corollary of Uniformly Variable Speed ​​Linear Motion (1)" Research on Uniformly Variable Speed ​​Linear Motion PPT Part 1 Content: Basic review of the two basic formulas for uniformly variable speed linear motion Speed ​​formula v = v0 + at, when v0 = 0, v = at Displacement formula x=v0t+12at2, when v0..

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Update Time: 2024-07-29

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