1. 10E3 Physics
Markus Norrby (NOM)

2. Physics – an experimental science
Physis (greek) means nature
We make models and use measurements to verify (or falsify) them
Example:
Experimental equipment: The ship HMS Endeavour
Result: a theoretical model of Australia

3. Make groups
Measure the length of the corridor

4. 0.1 Measurements and uncertainty
The result of a measurement is a value AND a unit
Always give a reasonable precision
176.8 cm (four significant figures)
177 cm (three s.f.)
180 cm (two s.f.)
If possible, give the measurement error
5.0 ± 0.5 cm (absolute error)
5.0 ± 10% cm (relative error)

5. Ch.1: Measurements and units
SI system: an international agreement on standard units
Based on 7 basic units
Quantity
Unit
Length s
Meter m
Time t
Second
Mass
Kilogram* kg
Electric current I
Ampere A
Temperature T
Kelvin K
Ammount of substance n
mole
mol
Luminous intensity
Candela cd
∗the only basic SI unit with a prefix
All other are derived units (combinations of the basic units)
Quantity
Unit
Velocity v
Meters per second
m s-1
Force F
Newton (= kilogram meters per second squared)
N (= kg m s-2)

6. We often need to convert between SI-units and other units
Ex. 1: a) how many meters are 2 ft? b) how many feet are 2 meters? (1 ft = m)
Ex. 2: How many km/h is 45 mph? (1 mile = 1609 m)

7. When dealing with large or small numbers we can use
Prefixes
Powers of ten
Ex. 3: Write m with: a) a prefix b) with a power of 10

8. Important tools: Task: measure the On page 22, answer 1,2,3,5
Vernier calipers
Micrometer
Stopwatch
Task: measure the
thickness of your hear
width of your shoe
time it takes for a shoe to fall from desk to floor
On page 22, answer 1,2,3,5