"Elastic Force Spring Dynamometer" Force and Motion PPT Courseware 2

Description

"Elastic Force Spring Dynamometer" Force and Motion PPT Courseware 2

think about it

Pull the spring, rubber band and squeeze the plasticine and dough with force respectively; after letting go, what is the difference in the result?

learning target

(1) Know what elasticity is;

(2) Be able to use the spring dynamometer correctly;

(3) Know that the greater the elastic deformation, the greater the elastic force.

1. Elasticity

Observation and Experimentation

1. Press a ruler lightly to deform it, and then remove the pressure. What phenomenon do you observe?

2. Stretch the rubber band, then let go and observe what happens to the rubber band.

3. After bending the wire and then letting go, what will you see?

elasticity and plasticity

1. Elasticity: When an object deforms and returns to its original shape when no force is applied, this property of the object is called elasticity.

2. Plasticity: When an object is deformed, it cannot automatically return to its original shape. This property of the object is called plasticity.

elasticity

When you press a ruler, pull a rubber band, or pull a spring, you feel their powerful effect on your opponent. This force is called elastic force.

elastic limit

The elasticity of the spring has a certain limit. Beyond this limit, the spring cannot fully recover. Therefore, when using the spring, do not exceed its elastic limit, otherwise the spring will be damaged.

2. Spring dynamometer

1. Principle of spring dynamometer

Principle: The spring deforms when it is subjected to pressure or tension. Within a certain range, the greater the tension or pressure, the greater the deformation of the spring.

2. Structure of spring dynamometer

A tool that measures force is called a dynamometer. A dynamometer made using the principle that the greater the tension on a spring, the longer it stretches, is called a spring dynamometer.

3. Use of spring dynamometer

1) Before use:

Use the first three to look at:

First look at the measuring range: observe the measuring range and choose a dynamometer with the appropriate measuring range.

2. Check whether the pointer is pointing at zero mark

Third, look at the minimum graduation value to determine the accuracy of the spring dynamometer.

2) When using:

Check later: Before measuring, gently pull it back and forth several times with your hands to avoid friction between the pointer, spring and housing, which may affect the accuracy of the measurement.

Second meeting: when measuring, apply force along the central axis of the spring

Three meetings: The line of sight should be perpendicular to the scale surface, and the dynamometer should be kept at rest or in a state of uniform linear motion.

Four-level reading: No need to estimate the reading, just read the value of whichever scale line the pointer is close to.

Note: When measuring upside down, the measured value will be larger.

Summary of this lesson

What did you gain from studying this class?

1. Elasticity

1. Elastic deformation and plastic deformation

2. Elastic force: The force exerted by an object on the object in contact with it due to its elastic deformation and its return to its original shape.

2. Spring dynamometer

1. Purpose: Measuring the size of force

2. Principle: The greater the force on the spring, the greater the deformation of the spring.

3. Structure: spring, dial, pointer, hook

4.Usage: three times before use, four times after use

Practice in class

1. Which of the following statements about elasticity is incorrect ( )

A. An object that undergoes elastic deformation will exert elastic force on the object it contacts.

B. The pressure, tension, etc. usually mentioned are all elastic forces in terms of the nature of the force.

C. The greater the deformation of the same object, the greater the elastic force.

D. Two objects can have elasticity without touching them.

2. Which statement about the spring dynamometer is incorrect ( )

A. The force applied to the spring dynamometer cannot exceed its range.

B. If the pointer does not point to the zero scale before use, it should be adjusted to zero.

C. When in use, the spring dynamometer can only be placed vertically

D. When in use, the pointer and spring cannot rub against the shell.

E. Before use, it is best to gently pull its hook back and forth several times.

3. The correct statement about elasticity is ( )

A. Only objects such as springs and rubber bands can produce elastic force

B. As long as the object deforms, elastic force will definitely be generated.

C. The elasticity of any object has a certain limit, so the elasticity cannot be infinite.

D. The size of the elastic force is only related to the degree of deformation of the object.

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For more information about the "Force and Motion Elastic Spring Dynamometer" PPT courseware, please click the Force and Motion ppt Elastic Spring Dynamometer ppt tag.

"Elastic Force Spring Dynamometer" Force and Motion PPT Courseware:

"Elastic Force Spring Dynamometer" Force and Motion PPT Courseware Review the past and learn the new: 1. What is force? Force is the action of an object on an object. 2. What are the functions of forces between objects? In physics, push, pull, lift, pressure, repulsion, attraction, etc. between objects are usually called forces.

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Update Time: 2024-10-04

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

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