usaha dan energi

WORK AND
ENERGY

MK: KONSEP DASAR IPA SD

Lecturer: Ibrahim, M. Pd

Program Studi PGSD
FKP Universitas Mataram

Multiple Choice

singkatan dari energi kinetik

• ep

• ek

• ea

• ed

Program Studi PGSD
FKIP Universitas Mataram

Source: https://giphy.com/gifs/nascar-racing-2021-motorsports-DpNOlWx7F77IG9stWa

Learning Objectives

T h r o u g h t h e q u e s t i o n a n d a n s w e r ,

i n f o r m a t i o n s e e k i n g a c t i v i t i e s , a s s o c i a t i o n

a c t i v i t i e s , a n d d i s c u s s i o n ,

1.

Students can analyze work concepts in every life
appropriately

2. Students are able to distinguish the concept of work

and non-work properly

3.

Students are able to analyze the difference between
kinetic energy, potential energy, and mechanical energy
properly.

Program Studi PGSD
FKIP Universitas Mataram

In everyday terms, work is
everything that is done by
humans.

In physics, work is defined as the force
acting on an object which causes the
object to move

The definition of work in physics is
very different from the definition of
work in everyday terms.

Program Studi PGSD
FKIP Universitas Mataram

What Is the Work?

W = F s

Program Studi PGSD
FKIP Universitas Mataram

Which of the following is doing the work?

Figure 1. Someone pushing the wall
Figure 3. A weightlifter

Figure 2. Girls pushing pick-ups

Program Studi PGSD
FKIP Universitas Mataram

The Work Done By A Constant Force

Figure 4. someone pulled the crate

Figure 4. shows a person pulls a crate of mass m a
distance s with a force of F. The direction of the pull
of the force forms an angle to the horizontal plane.
Therefore, the amount of work done by the force
by forming the angle is formulated as

The Work Done by A
Varying Force

Figure 6. The work done by a non-
constant force

Figure 5. Someone is pulling the bowstring

Contoh usaha yang dilakukan oleh gaya tidak konstan
ditunjukkan melalui kegiatan memanah seperti Gambar
5. Dalam kegiatan memanah, untuk melepaskan anak
panah dari busurnya diperlukan tarikan tali busur
beserta anak panah ke belakang. Semakin kuat
tarikannya, semakin besar gaya yang dirasakan oleh
pemanah.
Contoh lain berupa pegas yang diregangkan. Ketika
pegas diregangkan, gaya yang dirasakan orang yang
meregangkannya semakin besar.

Program Studi PGSD
FKIP Universitas Mataram

𝑊! = 𝐹"∆𝑥

𝑊 = &

"!

""

𝐹"∆𝑥

lim
∆"→%&

"!

""

𝐹"∆𝑥 = *

"!

""

𝐹"𝑑𝑥

𝑊 = *

"!

""

𝐹"𝑑𝑥

Kinetic Energy

Figure 7. The force F causes the object to move a distance s

An object that is initially at rest will
move when a sufficient force is applied.
Moving objects have the ability to do
work so it can be said to have energy.
The energy due to this movement is
called kinetic energy

Program Studi PGSD
FKIP Universitas Mataram

Potential Energy

Figure 8. head falling from
the tree

Potential energy is energy stored in an object or in a
certain state. Examples of potential energy are
gravitational potential energy and spring potential
energy. In addition, nuclear light and geothermal
energy also store potential energy.

Program Studi PGSD
FKIP Universitas Mataram

Mechanical Energy

Di alam semesta ini, tidak ada energi yang
dapat diciptakan ataupun dihilangkan.
Energi hanya dapat berubah bentuk dari
bentuk energi yang satu menjadi energi
yang lain. Jika terdapat energi yang telah
terpakai, akan dihasilkan energi dalam
bentuk lain yang besarnya sama dengan
energi semula.

Program Studi PGSD
FKIP Universitas Mataram

Total Energi Mekanik:

EM=EP+EK

PENERAPAN ENERGI MEKANIK
DALAM KEHIDUPAN SEHARI-HARI

Program Studi PGSD
FKIP Universitas Mataram

Animation of Mechanical Energy

Program Studi PGSD
FKIP Universitas Mataram

Cek Lebih lengkap di Google Classroom

Conclusion

Program Studi PGSD
FKIP Universitas Mataram

1. Work
2. Kinetic Energy
3. Potential Energy

Program Studi PGSD
FKIP Universitas Mataram

References

Program Studi PGSD
FKIP Universitas Mataram

ANY QUESTION?

THANK YOU JJ

Program Studi PGSD
FKIP Universitas Mataram