FISIKA KELAS XI: FLUIDA STATIS (PART 1) Tekanan dan Hukum Pascal

Summary

This educational video script covers the topic of static fluids in physics for 11th-grade students. It explains the concept of static fluids, which can be liquids or gases at rest. Key points include pressure, defined as force per unit area, Pascal's law stating that pressure in a confined fluid is transmitted equally in all directions, and Archimedes' principle. The script also discusses hydrostatic pressure, surface tension, capillarity, and viscosity. Practical applications like hydraulic lifts and pumps are mentioned, along with examples to calculate pressure and hydrostatic pressure.

Takeaways

• 📘 Fluida statis refers to fluids in a stationary state, including liquids and gases.
• 💧 An example of static fluid is water in a glass, which remains still unless acted upon.
• 📏 Pressure is defined as the force exerted per unit area on the surface of an object and can be mathematically expressed as P = F/A.
• 🧱 A practical example of pressure is calculating the force a block exerts on the ground, where its weight and surface area are factors.
• ⚖️ Pascal's law states that pressure exerted on a confined fluid is transmitted equally in all directions, useful in devices like hydraulic jacks and brakes.
• 🚗 Another application of Pascal’s law is lifting heavy objects using hydraulic systems, where force is applied through a smaller area to lift a larger mass.
• 🌊 Hydrostatic pressure is the pressure exerted by a fluid due to its depth and is influenced by factors such as fluid density and gravity.
• 🐠 The formula for hydrostatic pressure is P = ρgh, where ρ is fluid density, g is gravity, and h is the depth.
• 📐 The hydrostatic principle also applies to connected fluid columns, where different fluid densities result in different heights but equal pressures.
• 🧪 In the example of a U-tube filled with two fluids of different densities, the heights of the fluids adjust based on their mass and density.

Q & A

What is the definition of fluid statics?

Fluid statics is the study of fluids at rest, which includes both liquids and gases in a state of equilibrium or rest.

What is pressure in the context of physics?

Pressure is defined as the force acting per unit area, mathematically represented as P = F / A, where P is the pressure in Pascals or N/m², F is the force in Newtons, and A is the area in m².

How is the pressure exerted by an object on a surface calculated?

The pressure exerted by an object on a surface is calculated using the formula P = F / A, where F is the force exerted by the object, typically its weight, and A is the area of contact.

What is Pascal's law and how does it relate to fluid statics?

Pascal's law states that a change in pressure applied to an enclosed fluid is transmitted undiminished to all portions of the fluid and to the walls of its container. This principle is fundamental to understanding fluid statics.

Can you explain the concept of hydrostatic pressure?

Hydrostatic pressure is the pressure exerted by a fluid at rest due to the force of gravity acting on it. It increases with depth and is calculated using the formula P = ρgh, where ρ is the fluid density, g is the acceleration due to gravity, and h is the depth of the fluid.

What is Archimedes' principle and how does it apply to fluid statics?

Archimedes' principle states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces. This principle is crucial in understanding buoyancy and is applied in fluid statics.

How is the total pressure experienced by an object submerged in a fluid calculated?

The total pressure experienced by an object submerged in a fluid is the sum of the hydrostatic pressure and the atmospheric pressure acting on the fluid surface. It is calculated as P_total = P_hydrostatic + P_atmospheric.

What is the hydrostatic paradox and what does it demonstrate?

The hydrostatic paradox, according to the principle of hydrostatics, states that all points at the same depth in a fluid at rest have the same pressure. This principle demonstrates that pressure in a fluid at rest is independent of the shape of the container.

What is viscosity and how does it affect fluid statics?

Viscosity is a measure of a fluid's resistance to flow. It affects fluid statics by influencing the internal friction of the fluid, which can impact the distribution of pressure within the fluid.

Can you provide an example of how Pascal's law is applied in everyday life?

Pascal's law is applied in hydraulic systems such as hydraulic lifts, presses, and brakes, where a small force applied to a small piston is amplified to move a larger piston, demonstrating the transmission of pressure.

What is capillarity and how does it relate to fluid statics?

Capillarity is the ability of a fluid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. It is related to fluid statics as it involves the interaction between the fluid and the walls of the container, influencing the fluid's behavior at rest.

Outlines

00:00

📚 Introduction to Static Fluids

In this educational video, Yusuf Ahmad introduces the concept of static fluids, which are substances that can flow, including liquids and gases, that are in a state of rest. The video covers topics such as pressure, Pascal's law, Archimedes' principle, surface tension, and viscosity. The first part focuses on pressure, defining it as the force exerted per unit area. An example problem is presented where a block with a mass of 15 kg is used to calculate the pressure it exerts on the floor, taking into account the gravitational force and the contact area. The explanation also touches on how pressure is applied in everyday life, such as in hydraulic pumps and lifts, illustrating Pascal's law, which states that pressure applied to an enclosed fluid is transmitted equally in all directions.

05:01

💧 Hydrostatic Pressure and Pascal's Law Application

The second paragraph delves into hydrostatic pressure, which is the pressure exerted by a liquid at rest due to gravity. It explains that hydrostatic pressure is calculated using the formula P = ρgh, where ρ is the fluid's density, g is the acceleration due to gravity, and h is the depth of the fluid. An example is given where a child tries to lift a one-ton rock using a hydraulic system, demonstrating how Pascal's law applies to the situation. The calculation shows that the force exerted by the child must be adjusted according to the areas of the pistons involved. The paragraph also discusses the total pressure experienced by an object under water, which includes both hydrostatic pressure and atmospheric pressure.

10:02

🌊 Hydrostatic Principle and Its Application

The final paragraph discusses the principle of hydrostatics, which states that all points at the same depth in a fluid at rest experience the same pressure. An example is provided where a U-tube is filled with two different liquids of different densities. The principle is used to calculate the height of one liquid based on the height and density of the other. The explanation shows how the pressures at different heights are equalized according to the hydrostatic principle, leading to a calculation of the unknown height. The video concludes with a reminder to subscribe and engage with the content, and an invitation for viewers to ask questions if anything is unclear.

Keywords

💡Fluid Statics

Fluid Statics is the study of fluids at rest. In the context of the video, it is the main theme and encompasses the study of pressure, buoyancy, surface tension, and viscosity in fluids that are not in motion. The video discusses various principles and laws related to fluid statics, such as Pascal's law and Archimedes' principle, which are fundamental to understanding the behavior of fluids in everyday applications like hydraulic systems.

💡Pressure

Pressure is defined as the force applied perpendicular to the surface of an object per unit area. It is a key concept in fluid statics and is measured in pascals (Pa). In the video, pressure is calculated using the formula p = F/A, where F is the force and A is the area over which the force is applied. An example given is a block with a mass of 15 kg exerting pressure on the floor, demonstrating how pressure relates to the weight of an object and the area over which it is distributed.

💡Pascal's Law

Pascal's Law states that a change in pressure at any point in a confined fluid is transmitted undiminished throughout the fluid. This principle is crucial in the operation of hydraulic systems. The video uses the example of a small and a large piston to illustrate how the pressure applied to the small piston is transmitted to the large piston, highlighting the application of Pascal's Law in devices like hydraulic jacks and pumps.

💡Archimedes' Principle

Archimedes' Principle is a fundamental concept in fluid statics that states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid displaced by the body. The video discusses this principle in the context of buoyancy and how it applies to objects submerged in fluids, such as the example of a fish experiencing hydrostatic pressure at a certain depth.

💡Hydrostatic Pressure

Hydrostatic pressure is the pressure exerted by a fluid at rest due to the force of gravity acting on the fluid. It increases with depth and is calculated using the formula P = ρgh, where ρ is the fluid's density, g is the acceleration due to gravity, and h is the depth. The video provides an example of a fish at a depth of 15 meters to explain how hydrostatic pressure is calculated and its impact on objects submerged in a fluid.

💡Surface Tension

Surface tension is a property of the surface of a liquid that allows it to resist external forces. It arises due to the cohesive nature of liquid molecules. Although not explicitly detailed in the script, surface tension is an important aspect of fluid statics and can affect phenomena such as capillarity and the ability of some insects to walk on water.

💡Viscosity

Viscosity is a measure of a fluid's resistance to gradual deformation by shear or tensile stress. It describes the internal friction of a moving fluid. The video touches on viscosity as one of the topics within fluid statics, although it does not provide a detailed explanation. Viscosity is crucial in understanding how different fluids flow and interact under various conditions.

💡Buoyancy

Buoyancy is the upward force exerted by a fluid that opposes the weight of an immersed object. It is directly related to Archimedes' Principle and is a key concept in understanding why objects float or sink. The video discusses buoyancy in the context of the pressure experienced by a fish in water, illustrating how the fish is affected by the pressure of the water and the external air pressure.

💡Hydrostatic Equilibrium

Hydrostatic equilibrium refers to the state of a fluid at rest where the pressure at every point is balanced in all directions. This concept is important for understanding the distribution of pressure within a fluid. The video mentions this principle when discussing how pressure varies with depth in a fluid, such as the pressure experienced by a fish at different depths in water.

💡Hydraulic Systems

Hydraulic systems use the principles of fluid statics to transmit force or motion through a fluid. They are used in various applications, such as lifting heavy objects or operating machinery. The video references hydraulic systems as an example of how the principles of fluid statics, like Pascal's Law, are applied in practical, real-world scenarios.

💡Capillarity

Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. It is related to surface tension and viscosity. Although not directly mentioned in the script, capillarity is an important phenomenon in fluid statics and can be observed in various contexts, such as the rising of liquids in narrow tubes or the spreading of liquids on surfaces.

Highlights

Introduction to Fluid Statics, a physics topic for 11th-grade students in their first semester.

Definition of fluid: any substance that can flow, including liquids and gases.

Definition of static fluid: a fluid in a state of rest.

Example of static fluid: water in a glass.

Physics concepts to be covered include pressure, Pascal's law, Archimedes' principle, surface tension, and viscosity.

Explanation of pressure: force per unit area.

Mathematical formula for pressure: p = F/A, where p is pressure in Pascals, F is force in Newtons, and A is area in square meters.

Example problem: Calculating the pressure exerted by a block with a mass of 15 kg on the floor.

Application of pressure concept in everyday life, such as in Pascal's law.

Pascal's law states that pressure applied to an enclosed fluid is transmitted equally in all directions.

Practical applications of Pascal's law in hydraulic jacks, lifts, and car jacks.

Example problem involving a child lifting a one-ton rock using a hydraulic system.

Introduction to hydrostatic pressure: the pressure exerted by a static fluid on all directions at a point.

Mathematical formula for hydrostatic pressure: P = ρgh, where ρ is the fluid's density, g is the acceleration due to gravity, and h is the depth of the fluid.

Example problem: Calculating the hydrostatic pressure experienced by a fish at a depth of 15 meters.

Total pressure experienced by the fish includes hydrostatic pressure and atmospheric pressure.

Introduction to the principle of hydrostatics: all points at the same horizontal level in a static fluid have the same pressure.

Example problem: Determining the height of water in a U-tube filled with different liquids.

Encouragement to subscribe, ring the bell, and share the video if found beneficial.

Invitation for comments if there are any unclear points in the explanation.

Transcripts

[Musik]

Halo assalamualaikum warahmatullahi

wabarakatuh Halo sahabat fisika jumpa

lagi dengan saya Yusuf Ahmad pada video

kali ini kita akan belajar tentang

materi fisika kelas 11 semester 1 yaitu

berkaitan dengan Fluida statis Oke

Seperti apa simak penjelasannya berikut

ini Oke sahabat fisika Apa sih itu

Fluida statis fluida itu sendiri

merupakan segala zat yang dapat mengalir

bisa zat cair ataupun juga zat gas nah

Fluida statis statis itu artinya diam

jadi Fluida statis adalah fluida dalam

keadaan diam contohnya misalnya adalah

air didalam gelas air didalam Gelas itu

dia dalam keadaan diam atau statis

nasabah fisika pada materi kali ini yang

akan kita pelajari nanti di

caranya berkaitan dengan tekanan

kemudian hukum Pascal hukum Archimedes

tegangan permukaan dan kapilaritas serta

viskositas Oke kita mulai dari yang

pertama berkaitan dengan tekanan Apa sih

itu tekanan ya tekanan itu didefinisikan

sebagai besar gaya yang bekerja pada

permukaan benda tiap satuan luas atau

secara matematis tekanan bisa dirumuskan

p = r three dimana P itu merupakan

tekanan satuannya dalam Pascal atau n

per m2 Erni adalah Gaya tekan satu hanya

dalam n dan hanya adalah luas permukaan

tekan satuannya dalam M2 Oke sahabat

fisika kita lihat contoh soalnya di sini

ada Sebuah balok bermassa

15 kg dengan ukuran empat kali 1,5 kali

dua meter Tentukan besar tekanan yang

diberikan balok terhadap lantai Oke kita

bahas pada balok tersebut balok tersebut

Dia memberikan Gaya tekan terhadap

lantai yaitu berupa gaya berat atau

airnya berarti = W dimana gaya berat the

way itu dirumuskan W = m * g sehingga

nilainya sama dengan 15 di kali gayanya

kita gunakan 10 meter per sekon kuadrat

gizi 15 sekali 10 tidak 150 n itu adalah

gaya tekannya yaitu dari gaya berat

balok nya kemudian permukaan balok yang

menyentuh lantai itu adalah bagian Sisi

alasnya sehingga luasan yang kita pakai

adalah luas alas dari baloknya toa =

luasnya jelas luas alasnya 4 kali 1,5

itu 6 M2 sehingga besar tekanan yang

diberikan balok terhadap lantai adalah

ingat tadi untuk mencari tekanan itu

dirumuskan p = f a tall pengennya

berarti sama dengan fc150 diberi hanya

enam yasaban di dalam 25 N per m2

nasabah fisika berbicara tentang konsep

tekanan ini ternyata konsep tekanan itu

banyak diterapkan dalam kehidupan

sehari-hari lo Contohnya yaitu pada

hukum Pascal menurut hukum Pascal bahwa

tekanan yang diberikan pada zat cair

Dalam suatu ruang tertutup itu akan

diteruskan sama besar ke segala arah

contohnya misalnya pada penampang pompa

hidrolik seperti dibawa

Hai Di sini ada penampang yang kecil dan

ada penampang yang lebih besar menurut

hukum Pascal bahwa tekanan pada

penampang kecil dan tekanan pada

penampang yang besar itu nilainya sama

atau secara matematis itu dapat

dirumuskan W1 = P 2 atau er satu persatu

= F2 perang dua Nah penerapan dari hukum

Pascal ini ini misalnya pada dongkrak

hidrolik rem hidrolik dan mesin press

hidrolik serta pompa ban sepeda dan

mesin hidrolik pengangkat mobil Nah kita

lihat contoh soalnya di sini ada seorang

anak hendak menaikkan batu bermassa satu

ton dengan alat seperti gambar berikut

jika luas penampang pipa besar adalah

250 kali

khas penampang pipa kecil dan tekanan

cairan pengisi pipa diabaikan Tentukan

gaya minimal yang harus diberikan anak

agar batu bisa terangkat merakit Abbas

nah ingat tadi berdasarkan hukum Pascal

berlaku F1 persatu = F2 pra dua Nah

disini pada penampang dua disini batu

tersebut Dia memberikan Gaya tekan

berupa gaya berat sebesar f = w atau m

kali G gimana dia masanya adalah satu

ton atau 1000 kg Jika likenya 10tip

biayanya sebesar Rp10.000 n kemudian

disini diketahui jika luas penampang

pipa besar adalah 200 kali luas

penampang pipa kecil atau berarti H2

Nyai

nilainya 250 kali dari A1 Nah kalau kita

subtitusikan kebersamaan ini berarti

jadinya F1 perasat to = F2 nya dari sini

Rp10.000 bagi aduannya nilainya telah

250/100 disini as satunya boleh kita

coret sehingga nilai F1 pnya hingga sama

dengan 10.000 dibagi 250 toh ya nilainya

adalah 40 n cukup mudah bukan Oke sobat

fisika masih berkaitan dengan tekanan

kali ini kita akan membahas tentang yang

namanya Tekanan hidrostatis Apa sih itu

tekanan hidrostatis hydro itu karena

artinya air statis artinya dia menjadi

Tekanan hidrostatis itu adalah tekanan

pada air yang diam atau tekanan

hidrostatis itu merupakan tekanan

diberikan oleh zat cair ke semua arah

pada titik ukur maupun akibat adanya

gaya gravitasi secara matematis Tekanan

hidrostatis dirumuskan PH = Roger H

dimana PH itu merupakan Tekanan

hidrostatis Roito merupakan massa jenis

zat cair g-nya adalah percepatan

gravitasi dan ha merupakan kedalaman zat

cair dari permukaan tanah di sini ada

sebuah contoh soal seekor ikan berada

pada kedalaman 15 meter dibawah

permukaan air seperti pada gambar jika

massa jenis air 1000 kg per M3

percepatan gravitasi bumi 10 m per sekon

kuadrat dan tekanan udara luar 10 ^ 5 Pa

Tentukan a Tekanan hidrostatis yang

dialami ikan B tekanan total yang

dialami kan nah oke kita bahas

bersama-sama kita bahas jadi yang a kita

diminta untuk menentukan Tekanan

hidrostatis yang di

ini oleh ikan ini tadi bahwa untuk

menentukan Tekanan hidrostatis itu

dirumuskan P = troll GH di situ kita

lihat massa jenis airnya adalah 1000g

nya 10 kedalamannya atau hanya adalah 15

m netim levelnya sama dengan 1310 digali

15 ya bb-nya = rp150000 bhaskar oke

kemudian yang B tekanan total yang

dialami ikan itu selain mendapatkan

Tekanan hidrostatis dari air dan

tersebut juga mendapat pengaruh tekanan

udara luar sebesar 10 ^ 5 Pa sehingga

tekanan totalnya tompe total sama dengan

ro GH dari tekanan hidrostatisnya

ditambah dengan tekanan udara luar atau

p06 jadi p-total sama dengan Roger hanya

dari yang ada di dada persyaratan

Rp50.000 hitam

Hai tekanan udara luarnya adalah 10 ^ 5

Pa kau tadi rp150000 plus 10 ^ 5 tukang

= 100.000 jadi tekanan totalnya sama

dengan 250.000 Pa wa cukup mudah bukan

oke nah kita lanjutkan masih berkaitan

dengan tekanan hidrostatis di sini ada

yang namanya hukum pokok hidrostatis Apa

sih itu Um pokok hidrostatis ya menurut

hukum pokok hidrostatis untuk menyatakan

bahwa semua titik yang terletak pada

satu bidang datar dalam satu jenis zat

cair memiliki tekanan yang sama contoh

bisnis ini misalnya ada sebuah pipa u

yang diisi dengan dua buah zat cair yang

berbeda dengan massa jenis Rossa to dan

RO2 dimana disini ketinggiannya berbeda

tinggi per permukaan

day-1 adalah H1 tinggi permukaan zat

2-nya adalah H2 maka berdasarkan hukum

pokok hidrostatis berlaku tekanan satu

buat op 1 = p 2 tahu sama dengan ro 1

dikali G dikali y 1 = RO2 dikali G

dikali H2 Oke kita langsung ke contoh

Soalnya saja biar lebih muda pipa u

diisi dengan air raksa dan cairan minyak

seperti terlihat pada gambar jika

ketinggian minyak H2 adalah 27,2 cm

massa jenis minyak 0,8 gram per cm3 dan

massa jenis HG atau air raksanya adalah

13,6 gram per cm3 tentukan ketinggian

air raksa atau H1 Oke sahabat fisika

berdasarkan hukum pokok hidrostatis maka

pada pipa u seperti ini berlaku rosato

dikali G dikali

itu sama dengan produa digali kiri

digali H2 naganya disini boleh kita

coret sehingga tinggal ro satu kali A1 =

RO2 dikali h2pro satu atau massa jenis

air raksanya disitu adalah 13,6 jika

lihat satu sama dengan ro 2-nya massa

jenis minyaknya 0,8 kali ketinggian

minyaknya adalah 27,2 sehingga

ketinggian air raksanya taura satunya =

0,8 digali 27,2 dibagi 13,6 kau 27,2

dibagi 13,6 itu kan sama dengan dua

sehingga A1 = 0,8 dikali 2 jam nilai

adalah 1,6 cm cukup mudah bukan nah nah

sahabat fisika itu dulu pembahasan kita

tentang Fluida statis kita lanjutkan

lagi di video berikutnya ya

Hai sebelum lanjut jangan lupa subscribe

dulu ya dan Nyalakan tombol loncengnya

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