Analysis:
SI units-
Si units is the standard International Metric system of measurements.
The metric system was introduced to australia to provide an easier system than the imperial system.
The metric system is a base 10 system (all units are done by powers of 10). The imperial use more complicated bases.
Metric eg; 1000 mm = 1m, 1000m = 1km (not confusing)
Imperial eg; 36 inches = 1 yard, 1760 yards = 1 miles (confusing)
Types of motion:
Rotational-pg 141 ( rochford book)
Vector and scalar quantities-
Scalar quantities are defined by only having magnitude and no direction.
Eg; distance (20m) , time (10 s) , mass (22.8 kg), speed (110 km/h).
Vector quantities have a magnitude and a direction.
Eg; displacement …show more content…
Dynamic (Also known as kinetic friction) : kinetic friction is when there is a relative motion.
^change the little S to K for kinetic friction^
Work
U = f x d
U = Work
F = force
D =distance
Eg: “the work done lifting a house brick of mass 3kg from the floor to a bench 1m high is”:
Work (U) = f = 3x10 = 30; d = 1m
=30x1 = 30J (J is joules which is unit of work)
Note; If the house is held stationary, d=0 thus no work is done
Energy and power
Energy: (see page 65 in rochford book for eg)
Only looking at mechanical energy which can come in two forms;
Potential energy (PE):
*If the brick is held 1m above the ground the brick has potential energy which is the energy a body has as a result of its position above the earth*
= mass (m) x gravity (g) x height (h)
Energy unit is Joules ( J )
PE = mgh = Answer J
Kinetic energy (KE):
*kinetic energy is the energy a body has because of its motion; eg ; dropping the brick from 1m height and seeing what the energy of the brick just before hitting the ground is*
= ½ mass (Kg) x velocity^2 (m/s)
Energy unit is joules ( J …show more content…
Polymers
Commonly called plastics and rubbers.
These are modified heavily to produce desirable properties.
Polymers have low electrical and thermal conductivities.
Polymers are softer, less dense and more corrosion resistant than metals.
Elastomers are polymers that have a structure that allow large extensions that are reversible such as rubber bands.
Destructive and non-destructive testing methods
Destructive tests destroy the test piece. Eg. An impact test on a motor vehicle.
Non-destructive test allow the test piece to be used after testing - Crack tests and most hardness tests are non-destructive.
Stress and strain diagrams
Young’s modulus and PLEA formula
Engineering drawing:
Orthagraphical -
Pictorial (isometric) -
Modulus:
Engineering