The University of New South Wales
PHYS1111
,PHYS1111
Bold (peach) – Week number and core focus
Italic and underlined (black) – Heading
Bold (black) – Subheading
Week 1: Introduction
Prefix list
The SI Unit Set
Mass: kg
Distance: m
Time: s
Temperature: K
Force: N
Speed/Velocity: m/s
The rules of significant figures
In a calculation, your answer should be presented at the same number of significant figures as the lowest s.f. input.
,Scalars and vectors
A scalar has only magnitude, while a vector has magnitude and direction.
- To express direction, one may use the terms ‘horizontal’ and ‘vertical’, or using a compass such as simple
direction, true bearing and compass bearing.
A special case, however, is where there is one dimension (moving along a straight line).
- In this case, a positive sign denotes ‘up’ and a negative sign denotes ‘down’.
Adding vectors
When adding vectors, we:
- Then, to determine the magnitude and direction of that vector, you may use graphical addition which
involves physically measuring the required quantities, or algebraic addition using trigonometry.
, Vector decomposition
To combine vectors, we also use trigonometry.
Vector addition via components
1. Sketch the vectors if not already provided.
2. Split the vectors into x and y components.
3. Sum the total x components for a total x, sum the total
y components for a total y.
4. Solve as per above.
NOTE: Direction is important, be sure to assign positive and
negative, for example.
PHYS1111
,PHYS1111
Bold (peach) – Week number and core focus
Italic and underlined (black) – Heading
Bold (black) – Subheading
Week 1: Introduction
Prefix list
The SI Unit Set
Mass: kg
Distance: m
Time: s
Temperature: K
Force: N
Speed/Velocity: m/s
The rules of significant figures
In a calculation, your answer should be presented at the same number of significant figures as the lowest s.f. input.
,Scalars and vectors
A scalar has only magnitude, while a vector has magnitude and direction.
- To express direction, one may use the terms ‘horizontal’ and ‘vertical’, or using a compass such as simple
direction, true bearing and compass bearing.
A special case, however, is where there is one dimension (moving along a straight line).
- In this case, a positive sign denotes ‘up’ and a negative sign denotes ‘down’.
Adding vectors
When adding vectors, we:
- Then, to determine the magnitude and direction of that vector, you may use graphical addition which
involves physically measuring the required quantities, or algebraic addition using trigonometry.
, Vector decomposition
To combine vectors, we also use trigonometry.
Vector addition via components
1. Sketch the vectors if not already provided.
2. Split the vectors into x and y components.
3. Sum the total x components for a total x, sum the total
y components for a total y.
4. Solve as per above.
NOTE: Direction is important, be sure to assign positive and
negative, for example.
