Force and pressure asks you to connect a push, the area it acts on and what happens as a result. It runs from the pressure a bag strap puts on a shoulder to why a boat floats and how a garage lift works.
The lessons below follow an order where each idea supports the next. If one skill is weak, start there. Otherwise, follow the order.
How do the parts connect?
Pressure in solids comes first: pressure = force ÷ area. Once that is clear, pressure in fluids follows, because pressure in a liquid depends on depth and density.
Buoyancy uses the pressure difference between the top and bottom of an object in a fluid. Hydraulic systems then use the way pressure passes through a liquid to multiply a force.
A small worked example
An invented school bag weighs 60 N. A thin strap touches the shoulder over 3 cm², and a wide strap spreads the weight over 12 cm².
Convert the areas to m²: 3 cm² is 0.0003 m² and 12 cm² is 0.0012 m². Pressure under the thin strap = 60 ÷ 0.0003 = 200 000 Pa. Pressure under the wide strap = 60 ÷ 0.0012 = 50 000 Pa.
The force is the same, but the wide strap gives a quarter of the pressure. That is why wide straps are more comfortable, and this one idea runs through the whole topic.
Who should start where?
- New to pressure: begin with calculating pressure from force and area.
- Comfortable with calculations, unsure why water pushes harder deeper down: go to comparing pressure in fluids.
- Floating and sinking questions: read explaining buoyancy conceptually.
- Ready for mixed questions: try the force and pressure practice set.
If you want a teacher to work through pressure questions with you, see online one-to-one Science tuition.