Resource 4: Examples of Physics in action

Teacher resource for planning or adapting to use with pupils

Examples of physics in action

Places to visit and examples you might see

PlaceExamples Physics principles they use
Garage or workshopHydraulic jacks

Pressure = force/area and pressure is transmitted through a fluid (oil), so input pressure = output pressure

Used as a ‘force multiplier’

Brace, screwdriver

Input force x input distance from axle = output force x output distance

A force multiplier

Building sitePulleys

Input force x distance it moves = output load raised x height it is lifted.

A force multiplier

Wheelbarrows and levers

Input force x input distance from wheel axle or pivot = output force x output distance from pivot

A force multiplier

Kitchen or bakeryCan openers, potato chippers, nut-cracker

Examples of levers as force multipliers, so small force exerted by operator on the handle produces a large force on the object:

Input force x input distance from pivot = output force x output distance

Knives and skewersNarrow blade edges and fine points cut into the material more easily because, for the same force, reducing the area increases the pressure
PlaygroundSeesaw

Another lever example: a lighter person sits further out to balance a heavier person.

Clockwise moment = anticlockwise moment

Farm/gardenShears/secateurs/ branch cutters

Force multipliers:

Input force x input distance from pivot = output force x output distance

Some examples of force multipliers

Hydraulic jack:

You use a small force but push further to raise the large load a smaller distance.

Input pressure = output pressure because the pressure is transmitted by oil.

  • narrow input piston cylinder with area A1 , small input force F1
  • wider output piston cylinder with area A2, larger output force F2
  • force on output piston

Levers , e.g. see-saw:

Clockwise turning force x distance from pivot = anticlockwise turning force x distance from pivot

Cutting tools e.g. secateurs, shears:

Resource 3: Everyday examples of pressure

Resource 5: Keeping things cool