1. Energy,
Work &
Power

2. ENERGY

3. ENERGY
E
NE
R
GOS
which
means
active or
containing
work.

4. Different kinds of Energy
Kinetic energy
Potential energy
Chemical energy
Heat energy
Light or radiant energy
Electrical energy
Nuclear energy
Sound energy.

5. Kinetic energy
-the energy in
moving objects. Also
called ‘movement
energy’.

6. Example:
A girl is writing

7. Potential energy
is energy stored in a system of
forcefully interacting physical
entities.

8. Example:
A biker on top of the hill.

9. Chemical energy
is the potential energy of a
chemical substance to
undergo a transformation
through a chemical reaction or,
to transform other chemical
substances.

11. an amount of thermal
energy being transferred
(in a given process) in
the direction of
decreasing temperature.

12. Ex. A cup of hot coffee

13. Radiant energy
is the energy
of
electromagneti
c waves
including X-rays,

14. Ex. Light from the sun, a window reflects
radiant energy, Electricity.

15. Electrical energy
-is the energy
carried by moving
electrons in an
electric conductor.

16. Ex. Microwave, Television,Computers,Phones.

17. Nuclear energy
the energy released
during nuclear fission or
fusion, especially when used
to generate electricity.

18. Ex. Fusion, power plant.

19. Sound energy
– released by vibrating
objects.

20. Ex. Buzzing bee, a horn of a
car, a alarm clock.

21. Formula for:
Kinetic energy
KE = W.V²
2g

22. Examples:
1. The weight of a bomb is 250kg.
If it strikes the earth with the speed
of 40m/s, what is its KE?
Given: w= 250 kg
v= 40m/s

23. Given:
w= 250 kg
v= 40m/s
Formula: KE= W.V²
2g
Solution: KE = (250kg)
2g
(40m/s)²
= (250kg)(1600m/s)
2g
= 320,000
2
KE = 160, 000

24. Advantages and Disadvantages of Energy
Advantages:
It makes our lives
easier and
comfortably. It
makes our works
faster, and it
contributes to our
entertainment and
relaxation.
Disadvantages:
It makes man
lazy. It makes our
environment
polluted, and it
adds to our bill
consumption.

25. Work

26. Work • When a force acts upon
an object to cause a
displacement of the object, it
is said that work was done
upon the object. There are
three key ingredients to work
- force, displacement, and
cause. In order for a force to
qualify as having
done work on an object,
there must be a
displacement and the force
must cause the
displacement.

27. There are several good examples of work
that can be observed in everyday life - a
horse pulling a plow through the field, a
father pushing a grocery cart down the aisle
of a grocery store, a freshman lifting a
backpack full of books upon her shoulder, a
weightlifter lifting a barbell above his head,
an Olympian launching the shot-put, etc. In
each case described here there is a force
exerted upon an object to cause that object
to be displaced.

28. Power

29. Power
is the rate at which work is
done. It is the work/time ratio.

30. For example, a rock climber
takes an abnormally long time to
elevate her body up a few meters along
the side of a cliff.
On the other hand, a trail hiker (who
selects the easier path up the
mountain) might elevate her body a few
meters in a short amount of time.