Factors Affecting the Amount of Pressure in Physics

Factors Affecting the Amount of Pressure – Physics makes a major contribution to human life. Through the laws of physics, many tools can facilitate various human activities. Like the hydraulic jack used to lift a car, it uses the pressure of a liquid from Pascal’s law.

Unfortunately, most people often feel bored when studying physics because there are so many formulas and numbers that have to be calculated or can be said to be the same as mathematics. When in fact, physics can be learned easily as long as you understand the basic concepts.

Well, one of the physics that is considered complicated is pressure. How did it happen? Because in the chapter on pressure, there are calculations, symbols, graphs, and pictures. In short, there are many aspects that need to be understood.

In this article, we will discuss pressure in easy-to-understand language so that Sinaumed’s can better understand the chapter on pressure. Come on, let’s look at the review of the factors that affect the amount of pressure below.

What Is Meant by Pressure?

In short, pressure is the amount of force acting per unit. This is the same as the principle that force can affect motion and changes in the shape of objects. For example, when you drive a sharp nail into a block of wood, the force (force) you apply causes the nail to sink into the block.

In addition to force, pressure is also related to area, temperature, and volume. In physics, the International (SI) unit for pressure is newtons per unit area (N/m2), while the symbol for it is P or p.

To make it easier to understand, try to imagine Sinaumed’s walking on soft ground. Every time you take a step, your footprints will appear on the ground, right? Well, these traces are evidence of pressure from the soles of your feet.

Generally, you’ll want to place your entire foot on soft ground so you don’t sink easily. If you walk on your tiptoes, your feet will sink quickly because the pressure on the ground is much greater.

So in conclusion, pressure is the amount of force exerted on a surface area. Meanwhile, the magnitude of the pressure is highly dependent on the magnitude of the force.

In physics there are lots of terms or laws that you have to remember. To make it easier, Sinaumed’s can use the Physics Dictionary book written by Cahya Budi Kartiawan to find explanations about terms in physics.

Factors Affecting the Amount of Pressure

1. Press Force

The first factor affecting the amount of pressure is, of course, the compressive force. In principle, the greater the compressive force applied, the greater the resulting pressure will be. For example like this, suppose you are repairing a study cupboard that has holes in your house. To close the hole, you have to use wood that is nailed firmly.

So, in order for the nails to stick through the wood and the surface of the cupboard, of course you have to put out a lot of force (force). Because, if you hit a nail with little force, the nail won’t stick properly. In fact, it might come off again after two or three hours.

So, the greater the power (force) exerted by the hammer on the nail, the greater the pressure generated, so that the nail sinks deeper. Vice versa, the smaller the force (force) applied, the less pressure is generated so that the nail will not stick perfectly into the wood.

2. Press Surface Area

In addition to the compressive force, the amount of pressure is also strongly influenced by the surface area of ​​the press. In principle, the greater the surface area, the smaller the pressure. That’s why a sharp knife is easier to cut food than a dull knife, why is that?

This is because a sharp knife must have a thinner edge than a dull knife. In other words, the compressed surface area is smaller. That way, the pressure received by the knife becomes greater, so you can cut or slice food easily.

On the other hand, a blunt knife has a thicker tip, so the pressing surface is also larger. The greater the surface area, the smaller the pressure received. That is why, a dull knife is more difficult to use to cut food.

Types of Stress

1. Pressure of Solids

A solid always has a length and a width which you often use to measure its area. As previously mentioned, pressure is affected by the surface area of ​​the press. The greater the surface area, the smaller the pressure received.

To understand this, let’s use the shape of a duck’s leg and a chicken’s leg as an example. Chickens and ducks have different habitats. Chickens are more likely to walk on solid ground, while ducks are more comfortable with soft ground. That is why the shape of chicken and duck feet is different.

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The surface of the chicken’s feet is smaller than that of ducks, the goal is that the chickens can walk nimbly on solid ground. With a small size, the pressure exerted on the ground is greater, so that it can support its larger body.

Meanwhile, ducks need bigger legs so they can walk on mud. The big feet make the pressure received by the mud or soil smaller, so the ducks don’t sink easily.

2. Liquid Pressure

Liquids and gases have many special properties, one of which is the ability to flow. That is why, both are classified as fluids. Well, this fluid will flow when there is a pressure difference. Like air flowing from a place of high pressure to a place of low pressure.

However, liquids at rest also have pressure, Sinaumed’s. This pressure is often referred to as hydrostatic pressure. Hydrostatic pressure is the pressure caused by the force that exists in the liquid on the area of ​​the compressive field. The amount of pressure on a liquid depends on its depth.

So, anything that is a liquid will exert a pressure whose magnitude depends on its depth. Therefore, divers must always wear wetsuits and breathing apparatus.

This equipment can protect them from hydrostatic pressure in the deep sea. Otherwise, the hydrostatic pressure will cause the diver to feel chest tightness or damage the eardrums. This is the reason why many traditional divers who do not use diving equipment experience hearing loss.

a. Pascal’s law

According to Pascal’s law, if you apply pressure to one part of the liquid, then the pressure will be transmitted equally in all directions. To prove it, you can prepare a plastic bottle filled with water. Then, tightly close the bottle so that the water does not leak.

After that, make several small holes on the surface of the bottle, then press the bottle firmly. Water will automatically come out through the small hole, right? So, let’s look at the water that comes out and that’s the proof of Pascal’s law.

Now, try to close some of the holes in the bottle, then fill it again with water. After that, press the bottle firmly and see that the water coming out of the hole will get farther away, why is that?

The reason is because the amount of pressure on a flowing liquid depends on the surface area over which the liquid flows. By closing some of the holes, the surface area of ​​the bottle is getting smaller, so the pressure received by the water is greater. Therefore, water can reach far places.

b. Archimedes’ law

A Greek mathematician named Archimedes said that when an object is immersed in a liquid, the object will experience a buoyant force equal to the liquid it displaces. In physics, this is known as Archimedes’ law.

To understand this, try to remember whether you ever carried your friend while swimming or not. If you have, surely you know that your friend feels lighter than when carried on land. Is not it? It’s like the water in a swimming pool helping to lift your friend’s weight.

So in short, because there is buoyancy, your friend’s weight can be reduced, so it becomes lighter than when he was lifted on land.

Archimedes’ law also states that there are three possibilities for objects that are in liquids, namely floating, floating, and sinking. What’s the difference between the three? Let’s discuss them one by one!

1) Floats

An object will float when placed in water if the mass of the water is greater than the mass of the object. This floating state is a state in which some objects are immersed in water and some are above the water.

Therefore, people who cannot swim must use aids such as floats to float on the water. Because, the density of the buoy is smaller than the density of water.

2) Drift

In contrast to floating, an object is said to float when all of its parts are submerged in the water, but not touching the bottom of the water. This situation can occur because the object’s density is the same as the fluid’s density. For example, like an egg dipped in water with a little salt added.

3) Drown

Drowning is a condition in which an object immersed in a fluid enters completely until all of its parts touch the bottom. This condition is caused because the density of the object is greater than the density of the fluid. some of those things, like iron or metal dipped in water.

3. Gas Substance Pressure

The oxygen that you breathe freely on this earth is one of the air particles that is suspended on earth by the force of gravity. The gravitational force itself is a strong force that is invisible and pushes the air down, so the air molecules have weight.

The molecular weight of the air then exerts a force on the earth’s surface, including everything on it. This is what is then referred to as air pressure or atmospheric pressure.

In principle, atmospheric pressure is the total weight of air above the surface at each atmospheric level. This pressure is inversely proportional to altitude. That is, the higher the atmosphere, the fewer air molecules pressing down so that the air pressure decreases.

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That is why, the lowlands (coastal areas) have high air pressure and it decreases at higher altitudes (mountain areas). If at the same altitude there is a difference in air pressure, strong winds will appear.

To prove the presence of pressure on gaseous substances, Sinaumed’s can do a simple experiment using a glass filled with water and hvs paper. The trick, first fill the glass with water until it is full then cover the top using hvs paper.

After it is completely closed, turn the glass upside down while holding the hvs paper by hand. Wait a moment, then release the hand holding the paper. The result is that the water in the glass will not spill because the air pressure received by the paper is greater than the water pressure in the glass.

A brief explanation of the types of pressure above is a brief introduction for you. If Sinaumed’s wants to learn more, in the Smart Pocket Book of Physics: Collection of Formulas and Applications for Class 10, 11, 12 SMA / MA compiled by the Scholar Partners Team there is a very complete explanation of pressure.

Application of Pressure in Human Life

After knowing the factors that affect the amount of pressure, then we also need to know what are the benefits of pressure on equipment or things in everyday life. Pressure is widely used as the working principle of various objects and equipment that help human life. Here are some examples and a brief explanation:

1. Hydraulic jack

A hydraulic jack is a tool used to lift a car while changing a flat tire or repairing damaged parts. Inside this tool, there are two tubes. One large and one smaller size.

The large tube is connected to a lever and serves to support the weight of the car. Meanwhile, the small tube serves to drain the fluid into the larger tube.

In principle, the smaller the surface area of ​​the tube, the greater the pressure generated. So, in a hydraulic jack, air is pumped into a small tube and then forwarded to a larger tube. As a result, the pressure on the large tube is strong enough to lift large loads such as cars.

2. Hydraulic lifting machine

Have you ever accompanied your father to a car wash and seen a device that lifts a car so that the underside can be thoroughly cleaned?

The lifting equipment is called a hydraulic lifting machine. The working principle of this tool is quite similar to that of a hydraulic jack. It’s just that, this machine uses oil (liquid fluid).

So, initially air will be pumped into a small tube, as in a hydraulic jack, then the resulting air pressure will be transmitted to a larger tube. Then, this pressure then pushes the oil in the large tube, so that the jack can move up and down.

3. Automatic faucet in water reservoir

If you have a water storage tank in your house, take a close look, surely the tank is placed in a high place, right? What is the reason? Yes, the goal is for the tank to get a lot of pressure, so it can drain water.

The water storage tank does use Archimedes’ law as its working principle. So, inside the tank is actually a float that becomes an automatic faucet, so the float is designed to float in the water.

That way, the float will move up along with the height of the water. If the water is empty, the float will open the faucet to allow water to flow and if the water is full, the float will close the faucet.

4. Submarine

In a submarine, there is a tank whose job is to regulate entry and exit of water, so that the submarine can go up or dive whenever needed. When the tank is filled with air, the submarine will float and surface.

However, if the tanks were filled with water, the submarine would sink into the water. Therefore, when the submarine is about to surface, the water in the tank must be removed and replaced with air.

5. Hot air balloon

A hot air balloon can float in the air because its density is less than the density of the air around it. The density of the hot air balloon itself can be controlled using the air temperature in the balloon.

So in principle, to make a hot air balloon fly high, the density of air in the balloon must be reduced by increasing its temperature. Remember, hot air is lighter than cold air.

Conversely, if you want to go down, the density of air inside the balloon is increased by turning off the combustion engine so that the temperature drops. As explained in the book Basic Physics 7th Edition written by Halliday, Resnick, Walker.

That’s the discussion about the factors that affect the amount of pressure, Sinaumed’s. It turns out that if studied seriously, physics is very close to everyday life, yes. Hopefully the information you get in this article will be useful in the future. See you next time, Sinaumed’s!

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