"Mechanical Energy" Mechanical energy, internal energy and their transformation PPT courseware 3

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"Mechanical Energy" Mechanical energy, internal energy and their transformation PPT courseware 3

able

Object______, we say that this object has energy, referred to as energy

The more work an object can do, the more energy it has______

kinetic energy

The energy an object has due to ______

The amount of kinetic energy is related to the ______ and ______ of the object. For objects with the same mass, the greater the ______ of the object, the greater its kinetic energy; for objects moving at the same speed, the greater the ______, the greater its kinetic energy

gravitational potential energy

The energy of an object subject to gravity is ______

The magnitude of gravitational potential energy is related to the ______ and ______ of the object. The greater the object's ______ and its position______, the more gravitational potential energy it has

elastic potential energy

The energy that an elastic object has due to ______

The magnitude of elastic potential energy is related to the magnitude of ______. The larger the ______ of the same elastic object, the more elastic potential energy it has.

Mechanical energy

______ and ______ are collectively called mechanical energy

The kinetic energy and potential energy of an object can be ______. In the process of mutual conversion of only kinetic energy and potential energy, the ______ of mechanical energy remains unchanged.

1. The difference between "an object can do work on the outside" and "an object can do work"

The ability of an object to do work on the outside and the work done by the object are two different concepts. Being able to do work externally means that an object has the ability to do work, and it has nothing to do with whether it does work or not. The more work an object can do, the more energy it has. The more work an object can do does not mean that the object must do more work. On the contrary, an object that does more work may not necessarily have more energy.

2. Mutual conversion of kinetic energy, gravitational potential energy, and elastic potential energy

In the process of mutual conversion of kinetic energy and gravitational potential energy, only gravity does work. When the kinetic energy of an object is converted into gravitational potential energy, the object's speed gradually decreases, the kinetic energy decreases, the height increases, and the gravitational potential energy gradually increases; when the gravitational potential energy of an object is converted into kinetic energy, the object's height gradually decreases, the gravitational potential energy decreases, and the speed increases, the kinetic energy gradually increases.

When the kinetic energy of an object is converted into elastic potential energy, the speed of the object gradually decreases, the kinetic energy decreases, the degree of elastic deformation increases, and the elastic potential energy increases; when the elastic potential energy of the object is converted into kinetic energy, the elastic potential energy of the object decreases, and the degree of elastic deformation decreases. Small, the speed gradually increases, and the kinetic energy increases.

【example】

Roller coaster is a very thrilling entertainment and leisure activity. The roller coaster sometimes rises from the lowest end of the track to the highest end, and sometimes flies down from the highest end (as shown in the picture). Disregarding friction, which of the following statements is correct ()

A. The mechanical energy of point A is less than the mechanical energy of point B.

B. Point A has the largest kinetic energy, point B has the largest potential energy, and point C has the largest mechanical energy.

C. In the process from A to B, the kinetic energy decreases, the potential energy increases, and the mechanical energy remains unchanged.

D. In the process from A to C, kinetic energy increases, potential energy decreases, and mechanical energy increases.

Analysis: Since friction is not taken into account, that is to say, no mechanical energy is converted into other forms of energy, so the total mechanical energy remains unchanged during the mutual conversion of kinetic energy and gravitational potential energy; the mass of the roller coaster remains unchanged during the entire movement, and the size of the gravitational potential energy It depends on the height, and the kinetic energy depends on the speed. Therefore, when the roller coaster is at point B, the gravitational potential energy is the largest and the kinetic energy is the smallest. At point A, the gravitational potential energy is the smallest and the kinetic energy is the largest. At point C, both the gravitational potential energy and the kinetic energy are between A and B. In the process from A to B, kinetic energy is converted into gravitational potential energy. The kinetic energy decreases and the potential energy increases. Therefore, option C is correct.

1. Which of the following objects must have kinetic energy ()

A.Car

B. Airplane

C.Ship

D.Flying eagle

2. Which of the following objects has elastic potential energy ()

A. The rising tide of sea water

B. An airplane flying at a constant speed in the air

C. Stretched rubber band

D. Object at rest on level ground

3. As shown in the figure, when the aircraft accelerates upward, which of the following statements is correct ()

A. The kinetic energy of the aircraft remains unchanged and the gravitational potential energy increases.

B. The kinetic energy of the aircraft increases, but the gravitational potential energy remains unchanged.

C. The kinetic energy of the aircraft increases and the gravitational potential energy increases

D. The kinetic energy of the aircraft decreases and the gravitational potential energy decreases

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For more information about the PPT courseware "Mechanical Energy, Mechanical Energy, Internal Energy and Its Transformation", please click on the Mechanical Energy ppt, Mechanical Energy, Internal Energy and its Transformation ppt tag.

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Update Time: 2024-11-19

This template belongs to Physics courseware Beijing Normal University Ninth Grade Physics Volume 1 industry PPT template

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