1. WORK, ENERGY AND POWER

2. Understand the concept of work, energy and power.1 2 3 4 5 6
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
OBJECTIVES

3. How are work, power, and energy related? PG.32
EQ:

4. DO YOU KNOW? 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?

5. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
What 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?

7. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
WORK is defined when a force is applied through a displacement on a system
Displacement

8. Define work, energy and power
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.

9. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
WORK is defined as product of the force and displacement of an object in the direction of force.
Read the following four statements and determine whether or not they represent examples of work.
A teacher applies a force to a wall and becomes exhausted.
A book falls off a table and free falls to the ground.
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.)
A rocket accelerates through space.

10. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
Formula of work is
W = FΔd
Formula of work when force and displacement are at an angle
W = FΔd (cos Ө)
Quantity
Variable
Unit
Work W
Joule (J)
Force F
Newton (N)
Displacement Δd
Meter (m)
Angle Ө
Degree (º)

11. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
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.

12. Example 1

13. Example 2

14. Example 3

15. Define work, energy and power
Outcomes:
Define work, energy and power
WORK
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

16. Define work, energy and power
Outcomes:
Define work, energy and power
POWER
Power is defined as ability to do work.
SI Unit : Watt (W)
Formula:
Joule
second
The Power of body…..
Strong and Fast…… (Big Force and small times..)

17. Define work, energy and power
Outcomes:
Define work, energy and power
ENERGY
Energy is defined as CAPACITY TO DO WORK.
SI Unit : Joule (J)
Many form.
Common one:
Kinetic
Potential
Electric
Chemical
Solar
Nuclear