WORK, ENERGY

AND POWER

OB

JEC

TIV

ES

Understand the concept of work, energy and power.

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Define work, energy and power.

Calculate the form of energy by using formula Kinetic Energy and Potential Energy.

State the principal of conservation energy.

Describe conversion from one form to another form

Apply the concept and formula of work, energy and power in solving the related problems. Calculate the efficiency of mechanical system efficiency

EQ

:

How are work,

power, and

energy

related?

PG.32

Q1: How many steps of batu cave stair?

Q2: What is the height of the stair? answer:

Q3: How to measure our work or energy when climb a stair?

Q4: How would increase your power rating when climbing upstairs?

DO YOU KNOW?

Outcomes:

Define work, energy and

power

WORKWhat does WORK mean to you?

Are you doing work when….

Lifting a weights?

Walking with a bag grocery in your hand?

Completing your homework assignment?

Writing essay?

https://www.youtube.com/watch?v=pDK2p1QbPKQ

Outcomes:

Define work, energy and

power

WORK is defined when a force is applied through a

displacement on a system

WORK

Displacement

Outcomes:

Define work, energy and

power

WORK

A force that acts opposite to the direction of motion of an object does negative work

No work (W=0) will be done when the displacement equals zero or when the force is perpendicular to the displacement.

Outcomes:

Define work, energy and

power

WORK is defined as product of the force and

displacement of an object in the direction of force.

WORK

Read the following four statements and determine whether or not they represent examples of work.

1. A teacher applies a force to a wall and becomes exhausted.

2. A book falls off a table and free falls to the ground.

3. A waiter carries a tray full of meals above his head by one arm straight across the room at constant speed. (Careful! This is a very difficult question that will be discussed in more detail later.)

4. A rocket accelerates through space.

Outcomes:

Define work, energy and

power

Formula of work is

W = FΔd

Formula of work when force and displacement are at an angle

W = FΔd (cos Ө)

WORK

Quantity Variable Unit

Work W Joule (J)

Force F Newton (N)

Displacement Δd Meter (m)

Angle Ө Degree (º)

Outcomes:

Define work, energy and

power

Check Point:

Apply the work equation to determine the amount of work done by the applied force in each of the three situations described below.

WORK

Exa

mple

1

Exa

mple

2

Exa

mple

3

Outcomes:

Define work, energy and

power

Closing Task:

I will differentiate between my definition of work and the Physics definition of work and state how work, power and energy are related

WORK

Outcomes:

Define work, energy and

power

POWERPower is defined as ability to do work.

SI Unit : Watt (W)

Formula:

t

WP

time

WorkPower

time

ntdisplacemeForcePower

Joule

second

velocityForcePower

The Power of body…..Strong and Fast…… (Big Force and small times..)

Outcomes:

Define work, energy and

power

ENERGYEnergy is defined as CAPACITY TO DO WORK.

SI Unit : Joule (J)

Many form.

Common one: Kinetic Potential Electric Chemical Solar Nuclear