"Force and Its Effects" Force and Motion PPT Courseware 2

Description

"Force and Its Effects" Force and Motion PPT Courseware 2

1. Force

1. In physics, push, pull, lift, pressure, repulsion, attraction, etc. between objects are usually summarized as actions.

2. Definition of force: Force is the effect of an object on an object. Symbol F

3. Unit of force: Newton

Abbreviation: cow

Symbol:N

The force used to lift two eggs is approximately 1N

2. Effect of force:

1. Force can change the shape of an object.

2. Force can change the motion state of an object.

The direction of motion of the ball rolling off the table occurs _________ because the ball is acted upon by _______.

When an object deforms or changes its state of motion, it can be judged that it has been acted upon by a force.

What is a change in movement status?

Inductive knowledge:

Force can change the state of motion of an object: changes in the state of motion include: from rest to motion, from motion to rest, change in speed, and change in direction of motion.

Targeted training

Example: In the following examples, the shape of the object changes under the action of force: ( )

A: Emergency brake.

B: Riding a bicycle to speed up.

C: After the football moving in a straight line touches the player, its direction of movement changes.

D: Pull the bamboo strip hard with both hands to bend it.

Example: Which of the following statements about force is incorrect: ( )

A: Only objects in contact with each other produce force.

B: When the child pushes the wall hard, he is also pushed by the wall.

C: When people sit on a soft sofa, they can find that the sofa is concave, which shows that the action of force can change the shape of an object.

D: The football player heads the ball, and the direction of the ball changes, indicating that the action of force can change the motion state of the object.

It can be seen from the above activities that the effect of force is related to the size, direction and point of action of the force. The size, direction and point of action of the force are called the three elements of force.

3. The three elements of force: the magnitude, direction and point of action of force are called the three elements of force. They can all affect the effect of force

How to draw force diagram

(1) Use the starting point or end point of the line segment to express the _____ of the force;

(2) Draw a line segment with an arrow along the direction of the force. The direction of the arrow indicates the ______ of the force;

(3) If there are several forces in the same diagram, the greater the force, the _____ the line segment should be. Sometimes the _____ of the force can also be marked next to the force diagram.

Experience: Stretch out your hand and gently hit your classmate. Does your hand feel pain? Does your classmate feel any pain?

Think about it: if you are sitting in a small boat and pushing another small boat hard, can the other boat push your boat away and stop it?

When you feel pain, your classmates will feel pain too. Pushing away another boat will push your boat backwards. This shows that the effects of forces are reciprocal.

4. The effects of forces between objects are mutual.

When one object exerts a force on another object, the other object also exerts a force on the object, so the effects of forces are reciprocal.

Notice

1. The object exerting force and the object receiving force are not absolute. Because force and action are mutual, every object is both a force-exerting object and a force-receiving object.

2. The object is the condition for the existence of force, which means that force cannot exist without the object;

3. Only one object cannot produce force. Only two objects must be present at the same time to produce force and interaction between them. That is, the force-exerting object and the force-receiving object exist at the same time.

summary

1. Force is the effect of an object on an object.

Unit of force: Newton Symbol: N

2. Effect of force

1. Force can change the motion state of an object.

2. Force can change the shape of an object.

3. The three elements of force and the schematic diagram of force

4. The effects of forces are mutual.

think about it

Every Chinese will feel proud after seeing the spectacular scene of our country's self-made new launch vehicle sending our Shenzhou spacecraft into space. This is the huge thrust generated by the launch vehicle that causes the spacecraft to gain a high speed in a short time and rush out of the atmosphere. This is a display of the effect of force.

So, who gave it this power?

Since the rocket has a downward thrust on the gas sprayed downward, the forces between the objects are mutual, so the rocket is also pushed upward by the gas.

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For more information about the PPT courseware "Force and Motion Force and Its Effect", please click the Force and Motion ppt Force and Its Effect ppt tag.

"Force and Its Effects" Force and Motion PPT Courseware:

"Force and Its Effects" Force and Motion PPT Courseware Knowledge Points 1. Force is the interaction between objects. Experience: Stretch out your hand and hit your classmate. Does your hand feel pain? Does your classmate feel any pain? Think about it: Sitting in a small boat and pushing another small boat can make you fatter...

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Update Time: 2024-07-05

This template belongs to Physics courseware Lu Jiao Edition Eighth Grade Physics Volume 2 industry PPT template

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