09 Materials Flashcards
What is the definition of density?
Mass per unit volume.
What is the equation of density?
Mass / volume (m/v)
What is the unit for density?
Kg m^-3 or g cm^-3
What is the symbol of density?
p
What is the density of pure water?
1000kg m^-3
What is the definition of precision?
The smallest non-zero reading that can be measured.
What does the uncertainty have to be bigger than?
The instruments precision.
When a quantity is found by raising another quantity to a power,how do you get the percentage uncertainty?
Multiply the percentage uncertainty of the original quantity by the power.
eg- d^3 —> %Ud x 3
When a quantity in multiplied or divided by another, how do you find the combined percentage uncertainty?
Add the values together.
If there is no range then what is the uncertainty?
The same as the precision
What does vernier mean?
2 scales that cross
How do you use a vernier micrometer?
•take a reading close to the jaws using the ratchet.
•read the main scale reading from the barrel and add this value to micrometer reading on the thimble where the 2 scales meet
How do you use vernier callipers?
Start by looking at where the 0 on the bottom scale meets the other scale. This gives the mm’s. Then look at which line on the bottoms scale lines up perfectly with the main scale. This gives the 100th’s of a mm.
What is this?
Digital callipers
What is this?
A vernier micrometer.
What is this?
Vernier callipers
