"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT

Description

"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT

Part One: Preview Perception

1. Mechanical energy

1. Concept: Kinetic energy, gravitational potential energy and elastic potential energy are collectively called mechanical energy.

2. An object can have both kinetic energy and potential energy.

2. Mutual conversion of kinetic energy and potential energy

1. Kinetic energy and potential energy can be converted into each other.

2. Conservation of mechanical energy: If only kinetic energy and potential energy are converted into each other, the total mechanical energy remains unchanged, or mechanical energy is conserved.

3. Utilization of water energy and wind energy

1. Moving water and wind have a lot of mechanical energy.

2. Utilization: Utilize wind energy and water energy to generate electricity, etc.

Mechanical energy and its transformation PPT, part 2: interactive classroom understanding

Judgment of energy conversion

(1) When judging what form of mechanical energy an object has and how different forms of mechanical energy are converted, the key is to analyze how the object's speed, height and degree of deformation change.

(2) Conversion of kinetic energy and potential energy

[Example] As shown in the figure, an artificial earth satellite orbits the earth along an elliptical orbit (the satellite has the highest speed at perigee and the smallest speed at apogee). Then the kinetic energy of the satellite is the largest at the ____________ point, and the gravitational potential energy is the largest at the ___________ point; When the satellite moves from perigee to apogee, the ___________ energy of the satellite is converted into ___________ energy.

This type of question is also a common question in the high school entrance examination. You must read the question carefully and analyze the process of object change in this phenomenon, how the mass, speed, and height change during this process, and then based on the factors that affect the magnitude of kinetic energy and potential energy, To determine the size changes and mutual conversion of kinetic energy and potential energy.

Analyze the conservation of mechanical energy when an artificial earth satellite orbits the earth along an elliptical orbit. Its kinetic energy is the largest and its gravitational potential energy is the smallest at perigee. Its kinetic energy is the smallest and its gravitational potential energy is the largest at apogee. When the satellite moves from perigee to apogee, its kinetic energy gradually decreases. Small, the gravitational potential energy gradually increases, and the kinetic energy is converted into gravitational potential energy.

Answer Near Earth Far Earth Motion Gravity Potential

Mechanical energy and its transformation PPT, part three: try application

1. Mechanical energy

1. A bird is flying in the air. Its kinetic energy is 15 J, its gravitational potential energy is 18 J, and its mechanical energy is _______J.

2. Conversion of kinetic energy and potential energy

2. (2016 Hainan High School Entrance Examination) Athletes stand on the ground and throw a table tennis ball vertically. After the ball hits the ground, it will bounce to a position higher than the original throw. Which of the following statements is correct ()

A. When the ball starts falling, its kinetic energy is zero.

B. The ball still has kinetic energy when it bounces to the original throwing position.

C. Potential energy is converted into kinetic energy during the rising process of the ball after leaving the ground.

D. The ball’s mechanical energy increases throughout its motion.

Since the table tennis ball does not fall freely, it is thrown downward by the athlete, so the speed of the ball when it starts to fall is not zero, so the kinetic energy is not zero, so A is wrong; according to the question, after hitting the ground, the ball will bounce higher than the original ball. position, so when the table tennis ball rebounds to its original position, it is still moving, that is, there is still kinetic energy at this time, so B is correct; during the rising process of the ball after leaving the ground, the mass remains unchanged, the speed becomes smaller, and the kinetic energy becomes smaller. At the same time, As the height increases, the potential energy increases, so the process is to convert kinetic energy into potential energy, so C is wrong; during the entire movement of the ball, it will rub with the air and collide with the ground, so it will lose part of the mechanical energy and the mechanical energy will decrease, so D mistake.

3. Among the following phenomena, kinetic energy is converted into gravitational potential energy ()

4. In the following examples, the elastic potential energy is converted into kinetic energy ()

A.The wind blows the leaves

B. The swing swings from high to low

C. The car moves along the winding mountain road at a constant speed

D. Pull the bent bow to shoot the arrow

3. Conservation of mechanical energy

5. As shown in the figure, a small ball slides freely from the top of a smooth curved surface from rest. If its gravitational potential energy at the top is 65 J, regardless of air resistance, the kinetic energy of sliding to the bottom is ()

A.35 J B.50 J C.55 J D.65 J

6. As shown in the figure, ignoring air resistance, the ball released from point A in the air has the same () when passing through two positions B and C.

A.Speed ​​B.Kinetic energy

C. Mechanical energy D. Gravitational potential energy

Keywords: Free download of PPT courseware for the second volume of eighth-grade physics published by the People's Education Press, PPT download of mechanical energy and its transformation, PPT download of work and mechanical energy, .PPT format;

For more information about "Work and Mechanical Energy, Mechanical Energy and its Transformation" PPT courseware, please click on the "Work and Mechanical Energy PPT Mechanical Energy and its Transformation PPT" tab.

"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT teaching courseware:

"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT Teaching Courseware Part One: Classification Practice of Knowledge Points Knowledge Point 1 Mechanical Energy and its Transformation 1. Kinetic energy and potential energy are collectively called _____ energy. An object falling from a height has a kinetic energy of 8 J...

"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT Download:

"Mechanical Energy and Its Transformation" Work and Mechanical Energy PPT Download Part One Content: Basic Knowledge Points 1 Mechanical Energy and its Transformation 1. Xiao Ming throws an iron ball from the second floor to the ground. During the falling process of the iron ball, the gravitational potential energy is converted into kinetic energy. . 2. The following phenomena..

"Water Energy and Wind Energy" Mechanical Energy and its Transformation PPT Courseware 2:

"Water Energy and Wind Energy" Mechanical Energy and its Transformation PPT Courseware 2 1. River flow energy 1. Water energy mainly refers to river flow energy and is the third largest energy source in my country. 2. River water flow energy comes from solar radiation and is a renewable energy source. 3. The principle of formation: Due to the radiation of the sun..

File Info

Update Time: 2024-11-24

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 2 industry PPT template

Preview