The Stiletto That Sank Into the Lawn
💪 The Stiletto That Sank Into the Lawn
Physics glossary
- What is pressure?
- The force acting per unit area on a surface. P = F / A
Pressure is the force acting per unit area on a surface. It tells us how concentrated a force is — a large force on a small area causes far more damage than the same force spread over a wide area.
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🧠 Memory Aids
The Pressure Triangle
Draw a triangle with P at the top, F on the bottom-left, and A on the bottom-right. Cover what you want to find:
- Cover P: F over A → P = F / A
- Cover F: P times A → F = P × A
- Cover A: F over P → A = F / P
Remembering the units
"1 Pa = 1 N on 1 m²" — one Pascal is one Newton of force spread over one square metre. The unit name honours Blaise Pascal, the 17th-century French mathematician who studied fluid pressure.
P = hρg — "Here Rho Goes"
The letters in P = hρg can be remembered as Here Rho Goes (h, ρ, g) — depth times density times gravity. The word "rho" (ρ) is the Greek letter for density.
Atmospheric pressure and altitude
"Higher up = less air above = lower pressure." Think of it as a pile of air pressing down on you. The higher you climb, the less of the pile is above your head.
Now try it yourself
Quiz · Question 1 of 15
What is the correct equation for pressure?
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This topic in real past papers
Every real exam question we've found on pressure, with a full worked answer.