"Gravity" force and machinery PPT courseware

Description

"Gravity" force and machinery PPT courseware

To raise suspicion?

1. Why do apples on trees always fall to the ground?

2. Why doesn't the atmosphere surrounding the Earth escape?

3. Why does the moon revolve around the earth?

learning target

1. Know the causes of gravity and the importance of gravity;

2. Know the direction of gravity and the object exerting force;

3. Be able to use a spring dynamometer to measure gravity, understand the relationship between gravity and mass, and remember the meaning of g;

4. Know the concept of center of gravity and know that the position of the center of gravity will affect the stability of the object.

Self-Study Guide 1: The Generation of Gravity

concept of gravity

Definition: The force exerted on an object due to the attraction of the earth is called gravity. The size of gravity is usually called weight.

Emphasis: Gravity is the force exerted on an object. The object exerting force is the earth, not the attraction of the earth.

three elements of gravity

Construction workers often use this kind of thing when building walls. Do you know what this is for? How does it work?

Self-study guide 2: Direction of gravity

1. Direction of gravity: vertically downward (perpendicular to the horizontal plane)

2. Application of the direction of gravity

Explore: Different objects generally experience different gravitational forces, some are greater and some are less. So what factors are related to the gravity exerted by an object?

Class surfing

1. Students, what is your quality? What about your gravity? (g=10N/kg)

2. The mass of two eggs is approximately 0.1kg. What is its gravity? (g=10N/kg)

3. The mass of classmate Zhang Hua is 50 kilograms. How many cows does he weigh? Classmate Wang Fang's weight is 392 N. What is her mass in kilograms?

center of gravity of object

The center of gravity of a regularly shaped object is at the geometric center of the object.

The center of gravity of irregularly shaped objects can be determined by the suspension method.

In-class training - intellectual surfing

1. Among the following statements about the center of gravity, which one is correct ( )

A. The point where gravity acts on an object is called the center of gravity

B. Only the center of gravity of an object is affected by gravity

C. The center of gravity of a cone with uniform mass distribution is at the midpoint of its axis.

D. The center of gravity of a sphere is always at the center of the sphere.

2. Use a spring balance to weigh the small ball hanging at rest below it vertically, then we have ( )

A. The pulling force of the ball on the spring balance is the gravity of the ball

B． The pulling force of the ball on the spring balance is equal to the weight of the ball

C. The object exerting force on the ball by gravity is a spring

D． The object exerting the force of gravity on the small ball is the earth

summary

1. Definition of gravity: the force exerted on an object due to the attraction of the earth, symbol G

2. The magnitude of gravity: The gravity experienced by an object is directly proportional to the mass of the object. That is G=m g

G — Gravity — Newton (N)

m — mass — kilogram (kg)

g — gravitational constant — 9.8 N/kg

3. Direction of gravity: vertically downward

4. The point of action of gravity: at the center of gravity of the object

Operation:

Classwork: Questions 2, 3, and 4 on page p17.

Tutorial (preview):

1. What is sliding friction?

2. What is sliding friction?

3. Factors affecting sliding friction

4. Methods to increase and reduce friction

Keywords: Forces and Machinery Teaching Courseware, Gravity Teaching Courseware, Guangdong and Shanghai Version 8th Grade Physics Volume 2 Physics PPT Courseware Download, 8th Grade Physics Slide Courseware Download, Forces and Mechanics PPT Courseware Download, Gravity PPT Courseware Download, .PPT format;

For more information about the "Gravity Force and Machinery" PPT courseware, please click the Gravity ppt Force and Machinery ppt tag.

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Update Time: 2024-06-25

This template belongs to Physics courseware Guangdong and Shanghai version of eighth grade physics volume 2 industry PPT template

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