Term 1 Week 2 2017

Fundamental Units and Compound Units

Fundamental Units used in Physics looked at and how they combine to make up all the other units used in Physics.

The Fundamental Units covered for Mechanics were:

Quantity	Symbol	Unit	Unit Symbol	Vector OR Scalar
Time	t	second	s	Scalar
Distance	d	metre	m	Scalar
Displacement				Vector
Mass	m	kilogram	kg	Scalar

These Fundamentsl Units make up all the other units we will be using in Mechanics:

Quantity	Symbol	Unit	Unit Symbol	Vector OR Scalar
Speed	v	meters per second	ms-1	Scalar
Velocity				Vector
Acceleration	a	meters per second per second	ms-2	Vector
Force	F	Newton = (kgms-2)	N	Vector
Pressure	P	Pascal = Nm-2 = (kgm-1s-2)	Pa	Scalar
Energy Work, Kinetic, Gravitational	E W Ek Ep	Joule = Nm = (kgm2s-2)	J	Scalar
Power	P	Watts = Js-1 = (kgm2s-3)	W	Scalar

Note:

• A Vector has a magnitude (size) and a direction
• A negative value for a vector means that it is  going in the opposite direction
• A Scalar has only a magnitude (size)

Veritassium video on the worlds roundest object and the kilogram 

average velocity = change in total distance ➗ change in total time

va.v.  = Δd/Δt

Note: "Δ" means "change in"

This can be put into triangles as shown below:

The triangles above can be used to quickly find the expression required.

average acceleration = change in velocity ➗ change in time

aa.v.  = Δv/Δt

The above formula can also be put into a triangle with "Δv" at the top

Using the acceleration formular to compare two objects acceleration

Homework:

Complete the worksheet on Speed/TIme/Acceleration