Ulangan Harian Teknik Dasar Otomotif

Limbah gas buang kendaraan bermotor dapat menyebabkan pencemaran udara. Gas-gas berbahaya yang dihasilkan oleh kendaraan seperti karbon monoksida, nitrogen dioksida, dan partikel-partikel berbahaya lainnya dapat mencemari udara dan mengganggu kualitas udara yang kita hirup. Pencemaran udara dapat memiliki dampak negatif pada kesehatan manusia, hewan, dan tanaman, serta dapat menyebabkan kerusakan pada lingkungan secara keseluruhan. Oleh karena itu, limbah gas buang kendaraan bermotor merupakan salah satu penyebab utama pencemaran udara.

Limbah oli bekas di bengkel mesin otomotif dapat menyebabkan pencemaran tanah. Limbah oli mengandung bahan kimia berbahaya seperti logam berat dan senyawa organik yang dapat mencemari tanah. Ketika limbah oli yang terbuang tidak dikelola dengan baik, dapat meresap ke dalam tanah dan mencemarinya. Pencemaran tanah dapat berdampak negatif pada kualitas tanah dan dapat merusak ekosistem tanah serta mengancam kesehatan manusia dan hewan yang berinteraksi dengan tanah tersebut. Oleh karena itu, limbah oli bekas merupakan sumber pencemaran tanah yang perlu dikelola dengan baik.

The correct answer is "Tenaga lebih besar." This means that the advantage of a diesel engine over a gasoline engine is that it has more power. Diesel engines are known for their high torque output, which allows them to generate more power and pull heavy loads. This makes them suitable for applications such as towing, hauling, and commercial vehicles.

The question asks for a heat source that does not pose a fire hazard. "Sumber api tertutup" translates to "closed fire source" which implies that the flames are contained and not exposed, therefore reducing the risk of fire. The other options, such as "sumber panas kimia" (chemical heat source), "sumber panas mekanis" (mechanical heat source), "sumber panas listrik dinamis" (dynamic electric heat source), and "sumber panas listrik statis" (static electric heat source), do not provide the same level of safety as a closed fire source.

The given options are describing the different steps in the four-stroke cycle of a motor. The steps include intake, compression, exhaust, and power. The term "bilas" is not commonly used in the context of a four-stroke cycle, which suggests that it is the odd one out and does not belong to the cycle. Hence, the correct answer is "Langkah bilas."

The goal of occupational health and safety is to protect workers from hazards and ensure their well-being in the workplace. Preventing accidents on the road is not directly related to occupational health and safety, as it falls under traffic safety regulations and responsibilities of the transportation authorities. The other options mention preventing and reducing losses, providing immediate assistance in case of accidents, and protecting workers from workplace accidents, which are all relevant to the objectives of occupational health and safety.

The given options are different metal forming processes. Casting, welding, forming, and machining are all processes used to change the shape of a workpiece. However, painting (or coating) the surface of a workpiece is not a metal forming process, but rather a finishing process. Therefore, the correct answer is "Teknik pengecatan" (Painting technique).

The correct answer is "Hisap – kompresi – usaha - buang." This is the correct sequence of the piston cycle in a 4-stroke engine. The piston starts by sucking in the air-fuel mixture (hisap), then it compresses the mixture (kompresi), followed by the power stroke where the mixture is ignited and expands, providing power (usaha), and finally, the exhaust stroke where the burnt gases are expelled (buang).

The given options are all related to safety and health at work, except for "Kebaikan" which means "goodness" in Indonesian. Therefore, "Kebaikan" is not an abbreviation for Keselamatan dan Kesehatan Kerja (Occupational Safety and Health).

In a 4-stroke 4-cylinder engine with a firing order of 1-3-4-2 and rotating at 2000 rpm, each cylinder will fire once every 2 revolutions. In 5 minutes, the engine will complete 2000 revolutions (2000 rpm x 5 minutes). Since each cylinder fires once every 2 revolutions, each cylinder will fire 1000 times in 5 minutes. Since there are 4 cylinders, the total number of times the spark plug will ignite in 5 minutes for all cylinders is 1000 times x 4 cylinders = 4000 times. Therefore, the correct answer is 10,000 times.

The correct answer is "Tipe C." Tipe C refers to fires involving electrical equipment and electrical panels. This classification is used to identify and address fires caused by faulty wiring, overloaded circuits, or electrical malfunctions. It is important to understand this classification in order to respond appropriately and effectively to electrical fires, using the correct extinguishing agents and safety procedures.

The correct answer is "Memperbaiki sifat logam." The purpose of the metal forming process is to improve the properties of the metal. This can include enhancing its strength, ductility, hardness, or other mechanical properties. The process may involve shaping, heating, cooling, or applying various treatments to achieve the desired improvements in the metal's characteristics.

The correct answer is "Proses squeezing". This is because the process of forming metal by applying force to make it flow through a mold is commonly known as squeezing. This process involves compressing the metal to change its shape and create the desired form. It is different from stretching or drawing, which involve pulling or elongating the metal to achieve the desired shape. Seamless refers to a different process of forming metal without any visible seams or joints.

The correct answer states that in a 4-stroke gasoline engine, both fuel and air are sucked in during the intake stroke, while in a diesel engine, only air is sucked in during the intake stroke. This explanation accurately describes the difference between the two engines in terms of the intake process.

When cylinder number 4 is still in the compression stroke, cylinder number 1 cannot have its valves adjusted. This is because the engine follows a firing order of 1-3-4-2, meaning that cylinder number 1 is the next cylinder to fire after cylinder number 4. During the compression stroke, the valves of cylinder number 1 need to remain closed in order to build up the necessary pressure for combustion. Therefore, the valves of cylinder number 1 cannot be adjusted while cylinder number 4 is still in the compression stroke.

In a 4-stroke, 4-cylinder engine with a firing order of 1-3-4-2 and rotating at 2000 rpm, each cylinder fires once every two revolutions. Since there are 60 seconds in a minute, and the engine rotates at 2000 rpm, each cylinder will fire 2000/2 = 1000 times per minute. Therefore, in 5 minutes, each cylinder will fire 1000 * 5 = 5000 times. Therefore, the correct answer is 5000 times.

The given question asks for the material that is not included in the list. The options provided are "Logam cair" (liquid metal), "Plastik yang bisa meleleh (termoplastik)" (meltable plastic), "Material yang terlarut air misalnya beton atau gips" (water soluble material such as concrete or gypsum), "Material lain yang dapat menjadi cair dan pasta" (other materials that can become liquid and paste), and "Logam padat" (solid metal). Among these options, "Logam padat" is the only material that is not included in the list. Therefore, it is the correct answer.

The correct answer is "Kekuatan konstruksi tabung harus diuji padat dengan air sesuai ketentuan" because it does not relate to the installation requirements for a lightweight fire extinguisher. The other options mention specific requirements such as the maximum range, maximum installation height, easy accessibility, and appropriate fire classification and fire load. However, testing the construction strength of the tube with water is not mentioned as a requirement for installation.

The correct answer is "Usaha". In a 4-stroke 4-cylinder engine with a firing order of 1-3-4-2, when cylinder number 1 is in the compression stroke, cylinder number 2 is in the power stroke. The power stroke is also known as the "usaha" stroke, where the fuel-air mixture is ignited and the piston is pushed down, creating power. Therefore, when cylinder number 1 is in the compression stroke, cylinder number 2 is in the power stroke.

Pekerjaan yang wajib menggunakan peralatan pelindung ini adalah Mencharge. Peralatan pelindung mata atau kaca mata digunakan untuk melindungi mata dari bahaya yang dapat terjadi saat melakukan pekerjaan seperti mengikir, mengecat, mengampelas, dan mengelas. Dalam hal ini, mencharge juga termasuk pekerjaan yang berpotensi membahayakan mata, sehingga peralatan pelindung ini diperlukan.

The correct answer is "Motor pembakaran luar dan pembakaran dalam". This is because the question is asking about the different types of internal combustion engines based on the way they obtain thermal energy through the combustion process. "Motor pembakaran luar" refers to external combustion engines, where the combustion process occurs outside the engine and then transfers the thermal energy to the engine. "Motor pembakaran dalam" refers to internal combustion engines, where the combustion process occurs inside the engine itself to generate thermal energy.

The correct answer states that to obtain one power stroke from the combustion of gas, two piston movements are required. This is correct because in a four-stroke engine, the piston moves down during the intake stroke to draw in the fuel-air mixture, then moves up during the compression stroke, followed by the power stroke where the combustion of the fuel-air mixture occurs, and finally moves down again during the exhaust stroke to expel the waste gases. Therefore, there are two piston movements involved in obtaining one power stroke.

When cylinder number 1 is in the compression stroke, cylinder number 4 is in the exhaust stroke. This means that the valves in cylinder number 4 are open during this time and cannot be adjusted. Therefore, the correct answer is cylinder number 4.

The given options are different classifications of metal forming. The correct answer, "Berdasarkan material benda kerja" (Based on the material of the workpiece), is a valid classification criterion for metal forming. Metal forming can be classified based on various factors such as temperature, type of force, shape of the workpiece, and stages of production. However, the classification based on the material of the workpiece is not a valid criterion for metal forming.

When cylinder number 1 is in the compression stroke, cylinder number 4 is in the exhaust stroke. This means that while cylinder 1 is compressing the fuel-air mixture, cylinder 4 is expelling the burned gases from the previous power stroke. This process is known as the exhaust stroke, which is represented by the term "Buang" in the given options.