"Gong" Mechanical and Gong PPT Courseware 3

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"Gong" Mechanical and Gong PPT Courseware 3

1. The definition of work:

When a force acts on an object and the object passes a certain distance in the direction of the force, it is said that the force has done work on the object. In other words, the object exerting force has done work on the object receiving force. (indicated by W)

2. Two necessary factors for doing work

(1) Analyze the following examples. Does the force do any work on the object?

(2) Several common situations of no work being done:

① Hard work without success (F=0)

② No effort, no effort (S=0)

③ F and S are perpendicular (F⊥S)

(3) Summarize the two necessary factors for doing work

One is the force acting on the object (F)

Second, the object has passed a distance (S) in the direction of the force.

1. Calculation of work:

(1) Regulation: Work is equal to the product of force and the distance traveled by the object in the direction of the force.

(2)Formula: W=Fs

S—distance traveled by the object in the direction of the force

(3) Unit of work: joule (J) 1 J＝1 N·m

Reinforcement exercises

1. During the competition, Olympic weightlifting champion Yang Xia quickly raised the 100 kg barbell over her head in the first stage. In the second stage, she kept the barbell firmly in the air for 3 seconds. All three referees showed the white light. , indicating that the weightlifting was successful. Regarding the work she does on the barbell when she lifts weights, which of the following statements is correct ( )

A. She did no work in the first stage

B. She did no work in the second stage

C. She has been doing work in both stages

D. She has not done any work in the two stages.

Ask students to think

A small ball weighing 5N slides down an inclined plane with an inclination angle of 300. The inclined plane is 1m long. Question: How much work does gravity do when the ball moves to the end of the inclined plane?

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For more information about the PPT courseware "Gong Machinery and Work", please click on the "Gong Machinery and Work ppt" tab.

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Update Time: 2024-10-24

This template belongs to Physics courseware Beijing Normal University eighth grade physics volume 2 industry PPT template

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