Pesiapan Formatif Fisika Kelas 8 : Usaha Dan Energi + Pesawat Sederhana
Questions and Answers
- 1.
Konverter energi yang mengubah energi listrik menjadi energi bunyi adalah ....
- A.
Aki
- B.
Dinamo
- C.
Teko litrik
- D.
Telepon
Correct Answer
D. TeleponExplanation
A telepon is a device that converts electrical energy into sound energy, allowing us to communicate through audio signals. When we speak into a telephone, our voice causes a diaphragm or a microphone to vibrate, which in turn converts the sound energy into electrical energy. This electrical energy is then transmitted through wires or wireless signals to another telephone, where it is converted back into sound energy, allowing the person on the other end to hear our voice. Therefore, a telephone is the correct answer as it converts electrical energy into sound energy.Rate this question:
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- 2.
Yang temasuk sumber energi yang dapat diperbaharui adalah ....
- A.
Batu bara
- B.
Minyak
- C.
Gas alam
- D.
Air
Correct Answer
D. AirExplanation
Air merupakan sumber energi yang dapat diperbaharui karena air dapat digunakan untuk menghasilkan energi listrik melalui pembangkit listrik tenaga air. Proses ini melibatkan penggunaan air yang menggerakkan turbin, yang kemudian menghasilkan energi mekanik yang diubah menjadi energi listrik. Selain itu, air juga dapat digunakan untuk menghasilkan energi panas melalui pemanasan air dengan tenaga matahari atau geothermal. Dalam kedua kasus ini, air dapat digunakan berulang kali dan tidak akan habis jika dikelola dengan baik.Rate this question:
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- 3.
Perubahan energi yang terjadi di pembangkit listrik tenaga air adalah ...
- A.
Listrik-kinetik-potensial
- B.
Kinetik-potensial-listrik
- C.
Kinetik-listrik-potensial
- D.
Potensial-kinetik-listrik
Correct Answer
D. Potensial-kinetik-listrikExplanation
The correct answer is "potensial-kinetik-listrik." In a hydroelectric power plant, the energy transformation starts with the potential energy of the water stored in a reservoir. As the water falls from a higher to a lower level, this potential energy is converted into kinetic energy. The moving water then drives the turbines, which convert the kinetic energy into mechanical energy. Finally, the mechanical energy is transformed into electrical energy by the generator, producing electricity. Therefore, the correct order of energy transformation in a hydroelectric power plant is potential energy, kinetic energy, and then electrical energy.Rate this question:
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- 4.
Buah mangga jatuh dari pohonnya, makin ke bawah ....
- A.
Energi potensial gravitasi makin kecil, energi kinetik makin besar
- B.
Energi potensial gravitasi makin besar, energi kinetik makin kecil
- C.
Energi potensial gravitasi makin besar, energi kinetik makin besar
- D.
Energi potensial gravitasi makin kecil, energi kinetik makin kecil
Correct Answer
A. Energi potensial gravitasi makin kecil, energi kinetik makin besarExplanation
As the mango falls from the tree, its potential energy due to gravity decreases because it is moving further away from its initial position. At the same time, its kinetic energy increases because it is gaining speed as it falls. Therefore, the correct answer is "energi potensial gravitasi makin kecil, energi kinetik makin besar" which translates to "potential gravitational energy decreases, kinetic energy increases".Rate this question:
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- 5.
Sebuah balik kayu ditarik sepanjang bidang mendatar oleh gaya 8 N hingga bergerak sejauh 5 meter. Usaha yang dilakukan oleh gaya itu adalah ....
- A.
160 Joule
- B.
80 Joule
- C.
40 Joule
- D.
20 Joule
Correct Answer
C. 40 JouleExplanation
The work done by a force can be calculated by multiplying the force applied by the distance over which it is applied. In this case, the force is 8 N and the distance is 5 meters. Therefore, the work done is 8 N * 5 m = 40 Joule.Rate this question:
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- 6.
Sebuah meja didorong diatas lantai oleh gaya 10 Newton hingga bergerak dengan kecepatan 15 m/s. Usaha yang dilakukan oleh gaya itu selama 10 detik adalah ....
- A.
3000 Joule
- B.
1500 Joule
- C.
750 Joule
- D.
500 Joule
Correct Answer
B. 1500 JouleExplanation
The work done by a force is equal to the product of the force and the displacement in the direction of the force. In this case, the force applied is 10 Newton and the displacement is 15 m/s for 10 seconds. Therefore, the work done is calculated as follows: Work = force x displacement = 10 N x 15 m/s x 10 s = 1500 Joule.Rate this question:
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- 7.
Sebuah motor dan pengemudinya diketahui memiliki massa 200 kg. Bergerak dengan kelajuan tetap 5 m/s. Berapakah besar energi kinetik motor dan pengendara tersebut ...
- A.
20000 Joule
- B.
10000 Joule
- C.
5000 Joule
- D.
2500 Joule
Correct Answer
D. 2500 JouleExplanation
The correct answer is 2500 Joule. The kinetic energy of an object is given by the formula KE = 1/2 * mass * velocity^2. In this case, the mass of the motor and the rider is 200 kg and the velocity is 5 m/s. Plugging these values into the formula, we get KE = 1/2 * 200 kg * (5 m/s)^2 = 1/2 * 200 kg * 25 m^2/s^2 = 2500 Joule. Therefore, the total kinetic energy of the motor and the rider is 2500 Joule.Rate this question:
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- 8.
Sebuah balok bermassa 5 kg tergantung di ketinggian 7 meter. Jika diketahui gravitasi bumi 10 m/s2, maka energi potensial balok terssebut sebesar ....
- A.
360
- B.
350
- C.
340
- D.
330
Correct Answer
B. 350Explanation
The potential energy of an object is given by the formula PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. In this case, the mass of the block is 5 kg, the acceleration due to gravity is 10 m/s^2, and the height is 7 meters. Plugging these values into the formula, we get PE = 5 kg * 10 m/s^2 * 7 m = 350 J. Therefore, the potential energy of the block is 350 Joules.Rate this question:
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- 9.
Sebuah linggis digunakan untuk mengangkat beban seberat 200 Newton. Pada linggis tersebut ditaruh penumpu pada jarak 2 meter dari beban. Berapakah kuasa yang harus diberikan jika panjang total linggis 4 meter ....
- A.
50 Newton
- B.
100 Newton
- C.
200 Newton
- D.
250 Newton
Correct Answer
B. 100 NewtonExplanation
A lever is a simple machine that helps lift heavy loads with less effort. It works based on the principle of torque, where the distance from the fulcrum (pivot point) affects the force required to lift the load. In this case, the lever is 4 meters long, with the fulcrum placed 2 meters away from the load. To balance the lever, the force applied on one side of the fulcrum must be equal to the force on the other side. Since the load weighs 200 Newtons, a force of 100 Newtons must be applied on the other side of the fulcrum to lift it. Therefore, the correct answer is 100 Newtons.Rate this question:
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- 10.
Berapakah keuntungan mekanis (KM) sebuah bidang miring jika panjang lintasan bidang miring 4 meter dan tinggi bidang miring tersebut 0,5 meter?
- A.
16
- B.
8
- C.
4
- D.
2
Correct Answer
B. 8Explanation
The mechanical advantage (KM) of an inclined plane can be calculated using the formula KM = Length of inclined plane / Height of inclined plane. In this case, the length of the inclined plane is given as 4 meters and the height is given as 0.5 meters. Plugging these values into the formula, we get KM = 4 / 0.5 = 8. Therefore, the correct answer is 8.Rate this question:
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Mar 20, 2023Quiz Edited by
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