FISIKA DASAR 1 Teknik

3. F
SFSSFW ∠≡⇒== θθcos.
F
AB
X
W

4. Dari ke dua gambar di atas, jelaskanDari ke dua gambar di atas, jelaskan
transformasi dan transfer energi yangtransformasi dan transfer energi yang
terjadi !!!!!!!!!!!!terjadi !!!!!!!!!!!!
F
AB
X
W

6. θθ coscos. FxxFxFW ===
Dot Product :

7. Berapa besar kerja yang dilakukan ???????

8. Kerja oleh gaya yang berubah

9. Work done by a variable force

11. Conservative Force
A conservative force may be defined as
one for which the work done in moving
between two points A and B is
independent of the path taken between
the two points.

12. For a constant force F which moves an object in a
straight line from x1 to x2 , the work done by the force
can be visualized as the area enclosed under the force
line below

13. For the more general case of a variable
force F(x) which is a function of x, the
work is still the area under the force curve,
and the work expression becomes an
integral.

14. Dalam bentuk integral garis, kerja
dinyatakan sebagai berikut :

15. DAYA (P watt)
Daya adalah kerja yang dilakukan setiap
satuan waktu.
Daya rata-rata :
Daya sesaat :
t
W
P =
VF
dt
dS
F
dt
dW
P .. ===

16. Kinetic Energy
(Ek Joule)
Kinetic energy is energy of motion. The kinetic
energy of an object is the energy it possesses
because of its motion. The kinetic energy* of a point
mass m is given by

17. Kinetic Energy Concept

18. More Detail on Kinetic Energy Concept

20. For any function of x, the work may be calculated as the area under the
curve by performing the integral

22. Potential Energy
Potential energy is energy which results from position or
configuration. An object may have the capacity for doing
work as a result of its position in a gravitational field (
gravitational potential energy), an electric field (
electric potential energy), or a magnetic field (
magnetic potential energy). It may have
elastic potential energy as a result of a stretched spring
or other elastic deformation.

23. Potential Energy Function
If a force acting on an object is a function of position
only, it is said to be a conservative force, and it can
be represented by a potential energy function which
for a one-dimensional case satisfies the derivative
condition
The integral form of this relationship is

24. Potential Energy Concept
The potential energy U is equal to the work
you must do to move an object from the
U=0 reference point to the position r. The
reference point at which you assign the
value U=0 is arbitrary, so may be chosen
for convenience, like choosing the origin of
a coordinate system.
The force on an object is the negative of the derivative of
the potential function U. This means it is the negative of the
slope of the potential energy curve. Plots of potential
functions are valuable aids to visualizing the change of the
force in a given region of space.

25. Spring Potential Energy
Since the change in Potential energy of an object between two positions is equal
to the work that must be done to move the object from one point to the other, the
calculation of potential energy is equivalent to calculating the work. Since the
force required to stretch a spring changes with distance, the calculation of the
work involves an integral.
The work can also be visualized as the
area under the force curve:

26. The general expression for gravitational potential energy arises from
the law of gravity and is equal to the work done against gravity to
bring a mass to a given point in space. Because of the
inverse square nature of the gravity force, the force approaches
zero for large distances, and it makes sense to choose the
zero of gravitational potential energy at an infinite distance away.
The gravitational potential energy near a planet is then negative,
since gravity does positive work as the mass approaches. This
negative potential is indicative of a "bound state"; once a mass is
near a large body, it is trapped until something can provide enough
energy to allow it to escape. The general form of the gravitational
potential energy of mass m is:
Gravitational Potential Energy

27. However, for objects near the earth the acceleration of
gravity g can be considered to be approximately
constant and the expression for potential energy relative
to the Earth's surface becomes
where h is the height above the surface and g is the
surface value of the acceleration of gravity.

28. Gravitational Potential

29. Gravitational Potential Integral

30. Energy of a Truck

31. Potential Energy

32. Potential Energy Derivative
If the potential energy function U is known, the force at any point
can be obtained by taking the derivative of the potential.

33. Potential Energy Integral
If the force is known, and is a conservative force, then
the potential energy can be obtained by integrating the
force.

34. Energy can be defined as the capacity for doing work. It may
exist in a variety of forms and may be transformed from one
type of energy to another. However, these energy
transformations are constrained by a fundamental principle,
the Conservation of Energy principle. One way to state this
principle is "Energy can neither be created nor destroyed".
Another approach is to say that the total energy of an isolated
system remains constant.
Conservation of Energy

35. Energy in Mass on Spring

36. Contoh lain dari aplikasi kekekalan
energi adalah gerak jatuh bebas
/vertikal.