Pressure & Forces | Physics for GCSE/IGCSE - Year 11 PDF Download

Pressure

• Pressure is described as the focus of a force or the force exerted per unit area.
• For instance, when a pushpin is pressed downward:
  • It penetrates the surface instead of moving upward toward the finger.
  • This occurs because the sharp tip concentrates force over a small area, resulting in greater pressure.

• Example 1: Tractors
  • Tractors are equipped with sizable tires.
  • This disperses the weight (force) of the tractor across a broad area.
  • Consequently, the pressure is diminished, preventing the heavy tractor from sinking into mud.
• Example 2: Nails
  • Nails feature sharp pointed tips with minimal surface area.
  • This concentrates the force, generating significant pressure over a small region.
  • As a result, the nail can be driven into a wall.
• The formula for calculating pressure at the surface of a fluid is:
  
• Pressure is denoted in the unit of Pascals (Pa).
• The area considered should consistently be the cross-sectional area of the object.
  • This refers to the area where the force acts perpendicular to it.
• The equation can be rearranged using a formula triangle:
  
• This equation indicates that:
  • When a force is distributed across a wide area, it leads to low pressure.
  • Conversely, if the force is concentrated over a small area, it yields high pressure.