Pressure · revision map · IGCSE 0625, Topic 1.8
TOPIC 1.8 · PRESSURE
CAMBRIDGE IGCSE PHYSICS 0625 · ONE-PAGE REVISION MAP
thelucidstem.com
PRESSURE1.8
What is Pressure
Pressure is the force acting on each unit of area.
p = F / A
F = force (N)
A = area (m²)
unit pascal (Pa)
1 Pa = 1 N/m²
A = area (m²)
unit pascal (Pa)
1 Pa = 1 N/m²
The same force on a smaller area gives a higher pressure. That is why a sharp knife or a drawing pin cuts, and why wide skis spread a load.
Pressure in a LiquidEXTENDED
Pressure rises with depth and with the density of the liquid.
Δp = ρ g Δhρ = density · g = field strength · Δh = depth
- It pushes equally in all directions at a point.
- Deeper water gives a stronger jet from a hole.
Using Pressure: Hydraulics
A liquid passes pressure on, so a small force on a small piston becomes a large force on a large piston.
- Pressure is the same throughout the fluid.
- Used in hydraulic brakes and lifts (force multipliers).
Pressure Connects Topics
- Gas pressure comes from particles hitting the walls of their container (Topic 2.1).
- A barometer measures atmospheric pressure; a manometer measures gas pressure.
- Differences in air pressure drive the weather.
- Whether an object floats depends on the upward pressure of the fluid around it.