This topic summary covers Knowledge Organiser: Pressure within Pressure for GCSE Mathematics. Revise Pressure in Ratio & Proportion for GCSE Mathematics with 12 exam-style questions and 2 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 6 of 6 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Knowledge Organiser: Pressure
Key Terms
- Pressure: The force applied per unit area
- Force: A push or pull measured in Newtons (N)
- Area: The surface over which the force is spread (m² or cm²)
- Pascal (Pa): The unit of pressure; 1 Pa = 1 N/m²
- Key relationship: Smaller area = greater pressure for the same force
Must-Know Facts
- Pressure = Force ÷ Area
- Force = Pressure × Area
- Area = Force ÷ Pressure
- 1 Pa = 1 N/m²
- Units must be consistent: if area is in cm², pressure will be in N/cm²
- Same force on a smaller area gives a higher pressure
Key Formulas
- P = F ÷ A
- F = P × A
- A = F ÷ P
- Use the PFA triangle: cover the unknown to find the formula
Common Mistakes
- Formula inversion: P = F ÷ A (not F × A) — cover P in the triangle to confirm
- Unit mismatch: Force must be in Newtons and area in m² to get Pascals (Pa)
- Area calculation: Make sure to calculate the correct area (e.g. rectangle = l × w) before substituting
- Confusing with density: Pressure = Force ÷ Area; Density = Mass ÷ Volume — don't swap these
Practice questions for Pressure
Which formula correctly defines pressure?
A woman weighs 650 N. She wears flat shoes (each with area 150 cm²) or stiletto heels (each with area 1 cm²). She stands on one foot. Explain why the stiletto heel exerts a much greater pressure on the floor than the flat shoe. Support your answer with a calculation.