M8.1 Flashcards
What is the SI system based on?
The metric system
How are laws of physics defined?
By fundamental units and basic quantities
What is the unit of measurement for mass?
Kilograms (kg)
How is the mass of one kilogram defined?
By a piece of platinum alloy at the office of weights and measurements in Paris
What is the mass of 1 kilogram the same as?
The volume of one litre of pure water at 4 Celsius
What is the unit of measurement for length?
Metres (m)
How was the metre established?
By the french government in 1790
How is a metre more precisely defined?
A certain number of wavelengths or particular colour of light
What is the unit for time?
Seconds (s)
How are seconds defined?
A fraction of the unchangeable speed of light
What is the unit for temperature?
Kelvin (k)
What is zero kelvin also known as?
Absolute zero (because its the lowest temperature possible)
How does the Kelvin scale work?
Starts at zero and only goes up
What is 1 kelvin equal to?
1 Celsius
What are the four fundamental units?
- mass
- length
- time
- temperature
What are the six basic quantities?
- speed
- acceleration
- power
- pressure
- force
- work
What is speed?
The distance that a moving object covers in a unit of time
Where does the word speed come from?
The latin word velocitas because speed and velocity are the same
How is speed calculated?
Distance
————
Time
What is acceleration?
The change in speed by the time during which the change takes place
How is acceleration calculated?
Change in velocity
————————-
Time taken
How is acceleration measured?
Metres per seconds squared
True or false that an object under the act of gravity has uniform acceleration?
True
What is the average unit for gravity?
9.8 metres per second squared
What does deca-newtons stand for?
10 newtons
How is weight calculated?
Mass x gravity
What is weight measured in?
Newtons
What is work?
When an object has moved over a distance