Work, Power, and Energy

Guru: Ni Kadek Melya Suryaningsih, S.Pd.,Gr. Kelas Target: 8B

Tahap M: Mulai dari Diri

Halo anak-anak hebat! Selamat datang di bab baru yang sangat seru dan dekat dengan kehidupan kita sehari-hari: Work, Power, and Energy (Usaha, Daya, dan Energi).

Apersepsi & Refleksi Awal
Pernahkah kalian mencoba mendorong tembok rumah sekuat tenaga sampai mandi keringat, tetapi tembok tersebut tidak bergerak sama sekali? Dalam bahasa sehari-hari, kalian pasti merasa sudah "berusaha" sangat keras. Namun, tahukah kalian bahwa dalam kacamata Sains (Fisika), apa yang kalian lakukan justru bernilai nol usaha? Mengapa bisa begitu ya?

Lalu, bayangkan saat kamu menaiki tangga sekolah menuju lantai dua. Apa bedanya jika kamu menaiki tangga tersebut dengan berjalan santai dibanding berlari secepat kilat? Energi yang dikeluarkan mungkin terasa berbeda, dan waktu yang dibutuhkan pun berbeda.

Motivasi Belajar
Memahami konsep usaha, daya, dan energi bukan sekadar menghafal rumus matematis. Konsep ini adalah dasar bagaimana mesin mobil bekerja, bagaimana atlet merancang strategi lari, hingga bagaimana panel surya menghasilkan listrik untuk rumah kita. Dengan memahami materi ini, kalian akan melihat betapa luar biasanya hukum alam mengatur aktivitas kita setiap hari!

Trigger Questions (Pertanyaan Pemantik)
Untuk memancing rasa ingin tahu dan nalar kritis kalian, mari kita renungkan pertanyaan pemantik berikut ini (silakan baca dan pahami dalam bahasa Inggris):

  1. About Work: "If you push a solid concrete wall with all your strength for an hour until you are completely exhausted, why does physics consider that you have done zero work? What must happen for an action to be called 'work'?"
  2. About Energy: "Where does the energy you use to run actually come from, and where does it go once you stop running? Can energy simply disappear into thin air?"
  3. About Power: "Two identical students carrying the same school bag go up to the second floor. Student A takes the stairs slowly in 1 minute, while Student B sprints up in 15 seconds. Did they do the same amount of work, and who expended more power? Why?"

Sudah punya gambaran jawabannya? Yuk, tuliskan tebakan atau pemikiran awal kalian pada kolom catatan/diskusi di bawah ini. Jangan takut salah, karena proses belajar dimulai dari rasa ingin tahu yang besar! Let's explore together!

Hasil Tugas Siswa (Mulai dari Diri) Pantauan Orang Tua

Belum ada siswa yang mengumpulkan tugas.
Pantauan Ruang Diskusi Hanya Baca
Kadek Dwi Aditya Siswa 20 Sep 11:22
1. Work: The wall does not move, so the work is zero.


2. Energy: It comes from food and changes into movement and heat. Energy does not disappear.


3. Power: They do the same work, but Student B uses more power because it takes less time.
Jessline Christabell Violina Siswa 20 Sep 11:43
1. About Work:
If we push a wall but it doesn’t move, the work done is 0 because there is no displacement. An action is considered work when a force causes an object to move.

2. About Energy:
The energy we use to run comes from the food our body processes into chemical energy. When we run, the energy changes into movement, heat, and other forms of energy. Energy does not disappear, it only changes form.

3. About Power:
Both students do the same amount of work because they carry the same bag to the same height. However, Student B uses more power because they do the same work in a shorter time15 seconds instead of 1 minute.
Jessline Christabell Violina Siswa 20 Sep 11:45
1. About Work:
Kalau kita mendorong tembok tetapi temboknya tidak bergerak, secara fisika work = 0 karena tidak ada perpindahan (displacement). Suatu aksi disebut work jika ada force dan displacement.

2. About Energy:
Energy untuk berlari berasal dari makanan yang diproses tubuh menjadi energi kimia. Saat berlari, energi tersebut berubah menjadi gerakan, panas, dan bentuk energi lainnya. Energy tidak hilang begitu saja, tetapi berubah bentuk.

3. About Power:
Keduanya melakukan work yang sama jika massa, tangga, dan ketinggiannya sama. Tetapi Student B has more power karena melakukan work yang sama dalam waktu yang lebih singkat 15 detik dibanding 1 menit.
I Komang Adnyana Putra Siswa 20 Sep 11:48
1. Work: The wall does not move, so the work is zero.


2. Energy: It comes from food and changes into movement and heat. Energy does not disappear.


3. Power: They do the same work, but Student B uses more power because it takes less time.
Ni Luh Putu Sumiani Melati Adila Putri Siswa 20 Sep 11:50
1.karena beton/dinding tersebut tidak berpindah melainkan tetap di posisi awal. Suatu benda bisa di katakan memiliki "usaha" Harus ada gaya yang diberikan pada benda dan benda tersebut berpindah tempat.
2. Energi tersebut berasal Dari makanan yang kita konsumsi, energi tersebut tidak hilang melainkan berubah bentuk menjadi energi panas (kalor) yang dilepaskan ke lingkungan sekitar melalui keringat atau suhu tubuh yang meningkat, Berdasarkan Hukum Kekekalan Energi, energi tidak dapat diciptakan maupun dimusnahkan.
3. Ya ke-2 siswa tersebut memiliki usaha yang sama, karena siswa B mengeluarkan daya lebih banyak, Siswa B memiliki daya lebih besar, Dan daya (power) adalah seberapa cepat suatu usaha diselesaikan.
English:
1. Because the concrete or wall does not move but remains in its original position. For "work" to be performed on an object, a force must be applied to it, and the object must undergo displacement (change its position). 2. That energy comes from the food we consume; it is not lost but rather transforms into heat energy, which is released into the surrounding environment through sweat or a rise in body temperature. According to the Law of Conservation of Energy, energy cannot be created or destroyed. 3. Yes, both students perform the same amount of work, but Student B exerts more power. This is because Student B has greater power, and power is defined as the rate at which work is completed.
I Dewa Ayu Made Gina Cantika Siswa 20 Sep 11:51
1. About Work:
I think it's zero because the wall doesn't move at all. I feel tired, but in physics it's not work because the wall stays still and there is no displacement.

2. About Energy:
The energy comes from the food we eat. When we run, the energy changes into movement energy and heat energy, that's why we sweat. When we stop, the energy doesn't disappear, it changes into heat.

3. About Power:
The work is the same because the bag is same weight and same height. But Student B has more power because he is faster and finishes in shorter time.
Ni Luh Putu Nadia Cahya Kusuma Siswa 20 Sep 11:56
1. About Work

English: Pushing a solid wall does zero work because the wall does not move. In physics, work happens when a force causes an object to move in the direction of the force.

Indonesia: Mendorong dinding tidak menghasilkan usaha karena dinding tidak bergerak. Dalam fisika, usaha terjadi ketika gaya menyebabkan benda berpindah searah gaya.

2. About Energy

English: The energy used for running comes from food stored as chemical energy. After stopping, the energy is mostly converted into heat and other forms of energy. Energy cannot simply disappear.

Indonesia: Energi untuk berlari berasal dari makanan yang tersimpan sebagai energi kimia. Setelah berhenti, energi sebagian besar berubah menjadi panas dan bentuk energi lainnya. Energi tidak dapat hilang begitu saja.

3. About Power

English: Yes, they do the same amount of work because they carry the same bag to the same height. Student B uses more power because the same work is done in a shorter time.

Indonesia: Ya, mereka melakukan usaha yang sama karena membawa tas yang sama ke ketinggian yang sama. Siswa B menggunakan daya lebih besar karena usaha yang sama dilakukan dalam waktu lebih singkat.
Komang Alyssa Dhirakarina Paryatni Putri Siswa 20 Sep 13:42
1. Physics considers pushing an immovable wall to be zero work because the wall does not move, meaning the distance traveled by the object is zero.

2. The energy you use to run comes from the food you eat, and it never simply disappears into thin air when you stop.

3. Yes, both students did the exact same amount of work, but Student B expended four times more power. Both students lifted the same total mass to the same height, meaning the gravitational work was identical. However, Student B completed the task much faster, which required a significantly higher rate of energy expenditure.
Ni Komang Ayuning Dewi Siswa 20 Sep 16:51
1.about work
because the wall doesn move at all. In physics,an action is only called work if the object actually moves when you push it. Since the wall stays in place,the work done is zero.

bahasa Indonesia:Karena temboknya gak bergerak sama sekali. Dalam fisika,suatu tindakan baru di anggap ada usaha kalau bendanya beneran geser pas di dorong. Berhubung temboknya Dian aja, usaha nya dianggap nol.

2.about energy
the energy comes from the food we eat. when we stop running,the energy doesn just vanish. it changes into body heat,sweat,and the sound of our footsteps

bahasa Indonesia: energinya berasal dari makanan yang kita makan sehari-hari. Pas kita ga berhenti lari, energinya gak hilang gitu aja,tapi berubah jadi panas tubuh,keringat,sama suara langkah kaki.

3.about power
work: they di the same amount of work because both students carry the same bag and climb to the exact same floor.
Power: student B expended more power because student B reached the top much faster.

bahasa Indonesia:Usahanya sama aja karena beban dan tinggi lantainya sama. Tapi dayanya siswa B lebih besar karena dia nyampe ke atas jauh lebih cepat
I Gede Dharma Krishna Paramudya Siswa 20 Sep 16:52
1. Work: The wall does not move, so the work is zero.

2. Energy: It comes from food and changes into movement and heat. Energy does not disappear.

3. Power: They do the same work, but Student B uses more power because it takes less time.
I Nyoman Ananta Ramadika Siswa 20 Sep 17:12
1. Work (Usaha)
Mendorong tembok selama satu jam dianggap tidak melakukan usaha dalam fisika karena tembok tidak berpindah. Usaha terjadi jika ada gaya yang menyebabkan benda berpindah.

2. Energy (Energi)
Energi untuk berlari berasal dari energi kimia dalam makanan yang disimpan dalam tubuh. Energi tersebut berubah menjadi gerak, panas tubuh, dan panas ke lingkungan. Energi tidak hilang, tetapi berubah bentuk.

3. Power (Daya)
Keduanya melakukan usaha yang sama karena membawa beban yang sama ke ketinggian yang sama. Namun, Student B memiliki daya lebih besar karena melakukan usaha tersebut dalam waktu yang jauh lebih singkat.
Rumus: Daya = Usaha ÷ Waktu.
Komang Asti Indrayanti Siswa 20 Sep 18:23
*1. Tentang Usaha*
Usaha = Gaya x Perpindahan (W = F x s). Tembok tidak berpindah (s = 0), jadi W = 0.
Syarat usaha: harus ada gaya DAN benda harus berpindah.

*2. Tentang Energi*
Energi lari berasal dari makanan (energi kimia). Energi tidak hilang. Saat berhenti, energinya berubah jadi panas (badan panas & berkeringat) dan suara. Energi hanya berubah bentuk.

*3. Tentang Daya*
Usahanya SAMA, karena berat dan tingginya sama.
Daya B lebih besar. Daya = Usaha / Waktu (P = W/t). Kerja sama tapi waktu B lebih cepat (15 detik vs 60 detik), jadi dayanya lebih besar.
Ni Kadek Dea Chika Lestari Siswa 20 Sep 19:37
[20/9, 20.35] dekra₩: 1. In physics, work is mathematically defined as the product of force and displacement: (W = F times s). When you push against a solid concrete wall, the wall undergoes no displacement whatsoever. Consequently, the physical work performed is zero, even though your muscles experience fatigue due to continuous contraction.
An action is considered to produce work only if a force is applied to an object and that object undergoes displacement.
[20/9, 20.35] dekra₩: 2. This energy originates from the chemical energy in the food we consume, which is then processed through metabolism.
The kinetic energy (motion) generated while running is converted into thermal energy (heat)—released into the surrounding environment, causing the body to feel hot and sweat—while a small portion is used for internal biological processes such as heartbeat and respiration.
According to the Law of Conservation of Energy, energy cannot be created or destroyed; it can only be transformed from one form to another.
[20/9, 20.36] dekra₩: 3. Yes, the work done is the same. The work required to move an object to a higher position is equal to the change in its gravitational potential energy. Student B is the one who expends more power.
Power is the rate at which work is done over time; since Student B takes significantly less time...
Komang Aqila Mutiara Kasih Siswa 20 Sep 20:53
Work: Focuses on the result how much force is applied to make an object move to a new place.
Energy: Comes from the food you ate this morning (Chemical Energy). Inside your body, this food energy is transformed into Motion Energy to move your legs.
Power: Focuses on speed—how fast that work is completed.
Ni Putu Dian Amanda Putri Siswa 20 Sep 21:06
bahasa inggris:

Work: Focuses on the result how much force is applied to make an object move to a new place.
Energy: Comes from the food you ate this morning (Chemical Energy). Inside your body, this food energy is transformed into Motion Energy to move your legs.
Power: Focuses on speed—how fast that work is completed.

bahasa indonesia:

Usaha: Berfokus pada hasil, yaitu seberapa besar gaya yang dikerahkan untuk memindahkan suatu benda ke tempat baru.
Energi: Berasal dari makanan yang Anda santap pagi ini (Energi Kimia). Di dalam tubuh Anda, energi dari makanan ini diubah menjadi Energi Gerak untuk menggerakkan kaki Anda.
Daya: Berfokus pada kecepatan—seberapa cepat usaha tersebut diselesaikan.
I Gusti Ayu Istania Pranandani Siswa 20 Sep 21:24
Work: No work because the wall does not move

Energy: energy comes from the food we eat

Power: Both do the same work, but student B has more power because B is faster
Kadek Sintya Maharani Siswa 21 Sep 06:53
Work: No work because the wall does not move

Energy: energy comes from the food we eat

Power: Both do the same work, but student B has more power because B is faster
Ni Luh Sarita Putri Eka Suari Siswa 21 Sep 06:54
1. About Work:
Pushing the wall does not move it, so the work done in physics is zero. For an action to be called work, a force must cause an object to move.
2. About Energy:
The energy used for running comes from the chemical energy in food. It changes into movement energy and some heat. Energy does not disappear, but changes form.
3. About Power:
Both students do the same amount of work because they have the same mass and reach the same height. However, Student B has greater power because they do the work in less time.
Formulas:
Work: W = F × s
Power: P = W/t