The document outlines key concepts related to work, energy, and power including defining these terms, calculating kinetic and potential energy using formulas, stating the principle of conservation of energy as it relates to the conversion of energy forms, applying these concepts to solve related problems, and calculating mechanical system efficiency. The goal is to understand these fundamental physics concepts and be able to measure, calculate and apply 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

3. 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: Who has a big power to delivered up
the stair?

4. Outcomes:
Define work,
energy and
power
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?

6. Outcomes:
Define work,
energy and
power
WORK is defined as product of the force and displacement
of an object in the direction of force.
Formula of work is
W=Fxs
F= Force in Newton
s = Displacement in meters.
Displacement
Unit of work is Joule.

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

8. Outcomes:
Define work,
energy and
power
Power is defined as ability to do work.
SI Unit : Watt (W)
Formula:
Power
P
Work
time
W
t
Power
second
Force displacement
time
Power
Joule
Force velocity
The Power of body…..
Strong and Fast…… (Big Force and small times..)

9. Let’s twist……

10. Outcomes:
Calculate the
form of energy
by using
formula
Kinetic Energy
and Potential
Energy.
Definition :
Kinetic energy is energy due to the motion.
Formula:
KE
SI Unit :
= ½ m v2
Where:
m = mass (kg)
v = velocity (ms-1)
Joule (J)
Kinetic energy
Mass, m of F1
car in kg

11. Outcomes:
Calculate the
form of energy
by using
formula
Kinetic Energy
and Potential
Energy.
Mass= 624 kg
A 624 kg of F1 car is moving at a speed of 150
km/h. Determine the kinetic energy of the car.
Given:
• Mass = 624 kg
• Speed = 150 km 1000m
h
1km
1h
3600s
41.67m / s
Kinetic energy = ½ m v 2
= ½ x 624 x 41.672
= 541753.34 Joule

12. Outcomes:
Calculate the
form of energy
by using
formula
Kinetic Energy
and Potential
Energy.
Definition : Potential energy is energy possessed by an
object due to its position or state.
Formula:
PE
SI Unit :
=mgh
Joule (J)
Where:
m= mass (kg)
g = gravitational
acceleration (ms-1)
h = height (m)
The cat has a
POTENTIAL
ENERGY at high
position.

13. A load with as mass 5 kg was lifted up
by a pulley to the height of 0.8 m for
pile work. (Use, g = 9.81 ms-2).
What is Potential Energy the load.
Solution
Ep = m g h
= 5 kg x 9.81 x 0.8m
= 39.24 J

14. Outcomes:
State the
principal of
conservation
energy
.
The principle of conservative of energy
states that:
1) Energy cannot be created and
destroyed
2) Energy can change from one
form to another form.
3) Total of energy is constant.

15. Outcomes:
Describe
conversion
from one form
to another
form

16. Outcomes:
Describe
conversion
from one form
to another
form
The roller coaster:
A: Potential energy
B: kinetic energy
C: Potential + Kinetic
changes alternately…
A
C
B

18. ENGINEERING SCIENCE BB101
Total energy is constant..
WORK
ENERGY
Kinetic
Energy
Potential
Energy
Perubahan
Tenaga
Principle of
Conservation
of Energy
POWER
BFZZ, JMSK, PTSB

19. Outcomes:
Apply the
concept and
formula of
work, energy
and power in
solving the
related
problems.
•
If little Nellie Newton lifts her
40kg body a distance of 0.25m in
2 seconds, then what is the
power delivered by little Nellie's
biceps?
Solution
•
The work done is,
W=Fxs
= mg x s
= 40kg (9.81) x 0.25 m
= 100 J
• Hence, the power is
P = W
t
= 100 J
2s
= 50 Watt
0.25m

20. Outcomes:
Calculate the
efficiency of
mechanical
system
efficiency.
Mechanical system efficiency
• Efficiency is the ratio between the useful power delivered by
the motor and the power that you supply to the engine.
• Efficiency has no unit and is usually expressed in%.
Efficiency of work
Work output
100 %
Work input
Efficiency of power
Power output
100 %
Power input