Soal Evaluasi Tekanan

When an object is submerged in a fluid, it experiences an upward force called buoyant force. The buoyant force is equal to the weight of the fluid displaced by the object. In this case, the weight of the object in air is 30 N, but when it is weighed in water, its weight is reduced to 20 N. This means that the object is displacing 10 N of water. Therefore, the buoyant force acting on the object is 10 N.

The correct answer is (1), (2), and (3). The given tools, kempa hidraulis (hydraulic press), rem hidraulis (hydraulic brakes), and dongkrak hidraulis (hydraulic jack), all work based on Pascal's law. Pascal's law states that when pressure is applied to a fluid in a confined space, the pressure is transmitted equally in all directions. In these tools, the application of pressure to a fluid causes the fluid to transmit that pressure to another point, allowing for the amplification of force or the control of motion. Therefore, all of these tools operate based on Pascal's law.

The correct answer is "bidang sentuh lebih kecil". When a pencil is clamped, the pressure at one end is greater than the end with the eraser because the area of contact is smaller. As a result, the force applied over a smaller area leads to a higher pressure.

The correct answer is 72 cmHg. The air pressure decreases as altitude increases. At higher elevations, such as on a mountain slope, the air pressure is lower compared to sea level. The given answer of 72 cmHg indicates a lower air pressure, which is consistent with being at a higher altitude.

When the bottle is filled with hot water and then sealed, the air inside the bottle expands due to the increase in temperature. As the bottle cools down, the air inside contracts, creating a lower pressure inside the bottle. At the same time, the air outside the bottle remains at a relatively constant pressure. The difference in pressure between the inside and outside of the bottle causes the bottle to collapse or dent, as the higher pressure outside pushes against the lower pressure inside.

The correct answer states that the pressure on a solid substance is directly proportional to the force applied and inversely proportional to the contact area. This means that as the force increases, the pressure also increases, and as the contact area decreases, the pressure increases. This relationship is consistent with the principles of pressure and is supported by scientific evidence and observations.

The correct answer is (1), (2), dan (4). This is because the hydrostatic pressure depends on the height of the liquid, which is represented by (1). The density of the liquid, which is represented by (2), also affects the hydrostatic pressure. Lastly, the force of gravity, represented by (4), plays a role in determining the hydrostatic pressure. Therefore, all three factors are necessary to calculate the hydrostatic pressure accurately.

A manometer is a device used to measure the pressure of gases or liquids in a closed container. It is commonly used in various industries and scientific experiments to monitor and control pressure levels. In this context, the question is asking for the instrument used to measure air pressure in a closed container, which is a manometer. A barometer measures atmospheric pressure, a voltmeter measures electrical potential difference, and a hydrometer measures the density or specific gravity of liquids.

The force exerted by the machine is directly proportional to the area of the cross-section. Since the area of the larger cross-section is 20 cm2, which is 2.5 times larger than the smaller cross-section (8 cm2), the force exerted on the larger cross-section will be 2.5 times larger as well. Therefore, the force lift on the larger cross-section will be 20 N * 2.5 = 50 N.

The height of the water on the left side of the U-shaped pipe is 10 cm. This can be explained by the principle of hydrostatic pressure. The pressure at any point in a fluid is determined by the height of the fluid column above it. Since the density of water is higher than the density of oil, the water column on the left side will be higher in order to balance the pressure with the oil column on the right side. Therefore, the height of the water on the left side is 10 cm.

When a gas is compressed at a constant temperature, the product of its pressure and volume remains constant. Therefore, if the pressure is halved, the volume must double in order to maintain the same product. Since the initial volume is 40 cm3, when the pressure is halved, the final volume will be 2 times the initial volume, which is 2 * 40 cm3 = 80 cm3. Therefore, the correct answer is 80 cm3, not 240 cm3.

The correct answer is "massa jenis bahan pembuat kapal sama dengan massa jenis air." This means that the density of the material used to make the ship is equal to the density of water. Since objects float when their density is less than the density of the fluid they are placed in, if the density of the ship's material is the same as water, it will be able to float on the water's surface.