The Pressure Point

Why it matters

A woman in stilettos dents a wooden floor an elephant walks over safely. Force isn't the whole story — it matters how much floor each newton gets.

The idea in plain words

Force per area. Tap the terms.

P = F ÷ A

A 30 kg school bag (g = 10): strap 3 cm wide vs 1 cm. Compare shoulder pressure.

Wide strap: one-third the pressure, three times the comfort

• pascal (N/m²): P — pressure — how concentrated the push is
• sharp design: small A — knives, needles, nails — cut and pierce by concentration
• broad design: large A — wide straps, foundations, tank tracks, camel feet — comfort by spreading
• Same F = 300 N; area triples with the wide strap
• P falls to one-third

Predict first

Same person, boots vs snowshoes. On snow, the snowshoes…

P = F/A. The weight is fixed; the AREA is your choice — and pressure obeys the ratio.

• spread the same force over more area — less pressure, no sinking — correct
• press harder — they're bigger
• make the person lighter

What you do

Slide from stiletto to snowshoe: punch through the snow, then float on it — same 600 N throughout.

Check yourself

Nails are pointed so that…

Concentration is penetration — the whole hammer blow lands on a pinpoint.

Tanks and bulldozers use wide tracks instead of wheels to…

Tonnes spread over metres of track — the machine 'snowshoes' across mud.

Pressure is measured in…

1 Pa = 1 N spread over 1 m² — a whisper of a unit; real life uses kPa.

• a small tip area turns your hammer force into enormous pressure — correct
• they look sharp
• they weigh less
• lower the ground pressure and avoid sinking in soft soil — correct
• go faster
• carry more fuel
• pascal — correct
• newton
• joule