Teaching Objectives and Learning Outcome Test:

one

mind in mind

1

field and has potential energy at that position equal to Wt = 500 J. Let the object fall freely

2

to the ground, where the potential energy of the object is Wt = 900 J.

a) Ask from what height above the ground did the object fall?

b) Determine where the potential origin was chosen?

c) Find the velocity of the object when it passes through the origin of potential energy.

Answer:

Question 1: The gravitational potential energy of an object at a height z above the ground is the form of interaction energy between the Earth and the object, calculated by the work of gravity acting on the object when the object falls from height z to the ground.

Expression: Wt= mgz.

The elastic potential energy of a spring when it is deformed is the energy of the spring when it is deformed, calculated by the work of the elastic force acting on it.

springs up when taking it from the form.

state of deformation

static state

Expression:

Question 2: Answer A.

W  1 k ( l )2

t 2

Question 3: Choose the positive direction of the z axis pointing up.

1 2

a) Wt  Wt  mg ( z 1  z 2 )  500  (900)  1400 J .

m.

z  1400  47.6

3.9.8

b) At the origin of potential energy, z = 0

W  mgz  500J � z

 500  17.0

t1 1 1

3.9.8 m

The initial position is 17m higher than the original position of the potential energy. The potential energy at the ground can be checked:

2

Wt  mgz

2  900J � z2

  900  30.6 m.

3.9.8

That is, the ground is 30.6 m lower than the position of the origin of potential energy.

2.9,8.17

c) v    18.25 m/s.

2.3.3. Teaching aids:

1. Teacher:

Real life examples to illustrate how objects with gravitational potential energy and elastic potential energy can do work.

2. Students:

Review the concepts of gravity, gravitational potential energy, and elastic potential energy learned in the 8th grade curriculum.

Review the concept of work and how to calculate the work of force.

2.3.4. Teaching and learning process:

2.3.4.1. Check, prepare starting conditions and pose the problem in the lesson:

Review old lessons, prepare departure conditions:

State the definition of work and the expression for calculating work in the general case?

State the concept of kinetic energy, the relationship between work and kinetic energy change?

between the work of the force

Problem proposal: In the following cases:

+ A heavy object is up high

+ The bow is drawn.

+ Hammer the machine at a certain height.

Do these objects have energy? Why? If so, what form of energy is it?

HS: Objects have energy because they have the ability to do work. That form of energy is potential energy.

How many types of potential energy are there?

HS: There are two types of potential energy: gravitational potential energy and elastic potential energy.

We know that the energy associated with mechanical motion is called mechanical energy. In the previous lesson, we learned about a form of mechanical energy, kinetic energy. In today's lesson, we will study the second form of energy, potential energy (the teacher writes the topic on the board).

2.3.4.2. Solving learning problems:

Problem 1: Concept of gravity.

Teacher activities

Maybe you are interested!

• Illustration of Teaching Organization Model Using M-Learning
• Objective Test Questions Used in Teaching the Lesson "Equation of a Straight Line"
• Results of Teachers' Implementation of Stages of the Teaching and Learning Process
• Designing teaching plans for the lessons Momentum - Law of conservation of momentum, Potential energy in Physics 10 textbooks in the direction of developing students' active cognitive activities in exploring and solving problems - 1
• Teaching Objectives of English Subject According to Competency Approach

Student activities

Problem 2: Concept of gravitational potential energy.

Teacher activities

Problem proposal: In grade 8, you learned that an object at any height

compared to the ground has the ability to do work

so objects store energy in the form of potential energy.

Consider the following example:

Release

a hammer from the degree

high z fall

down to hit the pile making the pile go deep into the ground a distance s.

What force acts on the hammer and does work when the hammer falls?

When the height z of the hammer increases, when the hammer

HS: Gravity acts and does work when the hammer falls.

HS: The higher the hammer height, the more the pile sinks.

fall, how much?

Pile settlement changes as

position

Overview: When the hammer is at height z relative to

ground, energy storage hammer. Form

This energy is called potential field.

weight

The gravitational potential energy of an object is the form of interaction energy between the Earth and the object; it depends on the position of the object in the gravitational field.

When falling from a height z greater, the weight

force acting on the hammer to generate power

large, hammer power

The larger (the more the pile sinks), the greater the potential energy of the hammer.

HS: Yes.

gravitational force of

So the potential energy of an object at a height

material

proportional to the degree

height of

something relative to the ground is defined object to ground.

like

position

which? (have connection)

what with

height of the object?).

An object at height z has potential energy because the object has the ability to do work. On the other hand, gravity acts on the object to do work.

during the falling process, so it can be calculated

gravitational potential energy of an object

through the work of gravity acting on the object.

Calculate the work done by gravity when the hammer falls from height z to the ground?

Notice: The energy value that an object has due to the object being at a height z above the ground

HS: Work done by gravity:

A = Pz = mgz.

HS: Write an expression defining gravitational potential energy.

Wt = mgz.

earth is called gravitational potential energy, sign

The signal is Wt, which is calculated by weight.

force that makes an object fall from a height to the ground

high

HS: Unit

of the world

weight

Wt = A = mgz.

Define the unit of potential energy?

Field is the unit of energy. [Wt] = J.

Introduce the concept of potential energy:

Potential energy is a relative energy quantity, depending on position in space. Therefore, the potential energy reference must be chosen.

Landmark

ability is taste

the place where

HS: Potential energy reference point chosen at the surface

the energy of the object is zero.

According to the above formula, where is the potential energy reference chosen?

However, one can also choose the potential energy reference at another position for convenience in calculation. Specifically, we consider the following problem:

Request to answer question C3:

If the potential energy mark is chosen at position O, then at which point:

potential energy = 0 ?

potential energy > 0 ?

potential energy < 0 ?

land.

HS: If we choose the potential energy point at

O then:

At O: Wt= 0. At A: WtA>0.

At B: WtB< 0.

Problem 3: Find the relationship between potential energy change and work of gravity.