What is Pressure? | Physics | Don't Memorise
TLDRThis script explores the concept of pressure, defined as force per unit area, with the SI unit Pascal named after Blaise Pascal. It illustrates how a smaller area of contact, such as a nail's tip, results in higher pressure, allowing it to penetrate a wall more easily than its flat side. The script also contrasts high-pressure applications like drills and knives with low-pressure uses such as snowshoes and tank tracks to demonstrate the practical implications of pressure in various scenarios. It concludes with a teaser about the pressure exerted by liquids, to be discussed in a subsequent video.
Takeaways
- 🔨 Hammering an iron nail with force applied to the flat side results in the pointed side piercing the wall due to the force being applied over a smaller area.
- 📌 The pointed side of the nail is more effective at piercing because it has a smaller area of contact, leading to higher pressure on the wall.
- 📚 Pressure is defined as the perpendicular force acting on an object's surface per unit area, measured in Newtons per square meter (Pascals).
- 🎖 The term 'Pascal' is named in honor of French scientist Blaise Pascal for his work in hydrostatics and hydrodynamics.
- 🔍 The pressure decreases when the area over which a constant force is applied increases, as per mathematical logic of fractions.
- 🪵 The example of a nail and wall illustrates that a smaller contact area (like the nail's tip) results in greater pressure and easier penetration.
- 🔪 Tools like drills and knives have pointed or sharp edges to reduce contact area and increase pressure for cutting or piercing.
- 🥾 Snowshoes increase the contact area with the snow, reducing pressure and preventing the user from sinking, unlike regular shoes.
- 🚜 Army tanks use steel tracks to distribute their weight over a larger area, reducing the pressure on the ground compared to wheels.
- 💧 The script hints at the application of pressure in liquids, which will be discussed in a subsequent video.
- 🛠 High and low pressure have various applications; high pressure is useful for piercing or cutting, while low pressure is advantageous for walking on surfaces like snow or for heavy machinery to move without causing damage.
Q & A
What happens when you hammer an iron nail on its flat side?
-When you hammer an iron nail on its flat side, the pointed side of the nail, which is in contact with the wall, applies force on the wall and tries to pierce it.
Why is it difficult to hammer the pointed side of the nail and push the flat side through the wall?
-It is difficult because the pressure applied by the tip of the nail on the wall is more than the pressure applied by the nail's flat surface due to the smaller area of contact at the tip.
What is the definition of pressure?
-Pressure is defined as the perpendicular force acting on the surface of an object per unit area on which it is acting, which can be mathematically expressed as force divided by area.
What are the SI units for force and area, and what is the resulting unit for pressure?
-The SI unit for force is Newton (N), for area is meter squared (m²), and the resulting unit for pressure is Newton per meter squared, also known as Pascal (Pa).
Why is the unit of pressure named Pascal?
-The unit of pressure is named Pascal in honor of the French scientist Blaise Pascal for his contributions in hydrostatics and hydrodynamics.
How does the area of contact affect the pressure applied?
-The pressure decreases if the area of contact increases while keeping the force constant, as pressure is inversely proportional to the area of contact.
Why is it easier for the tip of a nail to penetrate through the wall compared to the flat side?
-The tip of the nail has a smaller area of contact with the wall, resulting in greater pressure and making it easier to penetrate the wall compared to the flat side.
What is the advantage of using a drill machine with a pointed tip to drill holes in the wall?
-A drill machine with a pointed tip applies more pressure on the wall due to the smaller area of contact, making it easier to create holes.
Why are sharp cutting edges more effective for cutting vegetables than blunt edges?
-Sharp cutting edges have smaller areas of contact, which increases the pressure applied to the vegetables, making it easier to cut through them compared to blunt edges.
What is the purpose of using snowshoes when walking on snow?
-Snowshoes increase the area of contact with the snow, reducing the pressure and preventing the feet from sinking deep into the snow.
Why do army tanks use steel tracks instead of wheels?
-Steel tracks provide a larger area of contact with the ground, reducing the pressure exerted on the ground compared to wheels, which would otherwise exert a massive pressure due to their smaller contact area.
Do liquids also apply pressure?
-The script does not provide information on whether liquids apply pressure, but it is mentioned that this topic will be covered in the next video.
Outlines
🔨 The Mechanics of Hammering a Nail
This paragraph explains the difference in pressure application when hammering the flat side versus the pointed side of an iron nail. When the pointed side is hammered, it pierces the wall easily due to higher pressure from a smaller contact area. The paragraph defines pressure as force per unit area, with its SI unit being Pascal (Pa). It highlights that a smaller area increases pressure when the force is constant, using examples like nails, drills, knives, and axes to illustrate the concept of high pressure. Additionally, it touches on how low pressure is beneficial in certain scenarios, like snowshoes preventing sinking in snow by increasing contact area.
🚜 The Importance of Low Pressure in Heavy Machinery
This paragraph discusses how low pressure is beneficial for heavy machinery like army tanks. Army tanks use steel tracks to distribute their weight over a larger area, reducing the pressure on the ground and preventing the wheels from sinking. This is contrasted with high pressure scenarios where solids exert force on other solids. The paragraph concludes with a teaser for the next video, which will explore how liquids also apply pressure.
Mindmap
Keywords
💡Force
💡Pressure
💡Area
💡Pascal
💡Hydrostatics
💡Hydrodynamic
💡Drill Machine
💡Cutting Edge
💡Snowshoes
💡Army Tank
💡Liquids
Highlights
Hammering the flat side of a nail applies force on the pointed side, allowing it to pierce a wall.
Hammering the pointed side and trying to pierce with the flat side is ineffective due to lower pressure.
Pressure is defined as force per unit area, with the SI unit being Pascal (Pa).
Increasing the area over which force is applied decreases pressure, as shown in the nail example.
The tip of the nail has a smaller area than the flat side, resulting in higher pressure and easier penetration.
Drill machines and cutting tools use sharp tips or edges to reduce area and increase pressure.
Using the blunt edge of a knife to cut is less effective due to larger area, resulting in lower pressure.
Axes have sharp edges to increase pressure on trees, facilitating cutting.
Snowshoes distribute weight over a larger area, reducing pressure on snow and preventing sinking.
Army tank wheels run on steel tracks to increase contact area and reduce pressure on the ground.
Higher pressure is beneficial for penetration, as seen in nails and cutting tools.
Low pressure is advantageous in preventing sinking in snow or damage to ground surfaces.
Pressure is influenced by both force and the area over which it is applied.
Vegetable cutting is more efficient with sharp edges due to higher pressure.
Examples demonstrate the practical applications of high and low pressure in everyday life.
Transcripts
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