Phys : misc

True or false : 30 000 kg is an accurate way of writing a mass to 2 sig fig ?

False : you should instead use scientific notation (standard form) : 3.0 * 10 ^ 4 kg

If given a graph e.g. v against h, and told to describe the relationship between v and h, what must you consider ?

Equation/s relating the two variables that could reveal the true relationship:

e.g. mgh = 1/2 mv^2

2gh = v^2

h is proportional to v^2

What pieces of measuring apparatus could produce the following reading ? : 7.33 mm

digital vernier callipers (not analogue - not precises enough)

micrometre

travelling microscope

What units is a vernier scale in ?

mm

What units is the main scale on vernier callipers / travelling microscope in ?

cm

When using a previous answer for a question, what must you ensure to do?

Use more significant figures than that of your final answer!

What must you do as soon as you see ANY graph?

Circle axis labels

Underline axis units

If a graph’s axes are labelled to 2sf, how precisly can we read the graph

To 3 sf

True or false? Ωm is an SI unit?

True (they’re just not a fundamental base unit)

What acronym can be used to remember the 6 SI fundamental units for the exam (so excluding candela)

MATT LC (“matt L C who just really likes base units”)

What are the 6 fundamental base SI units?

Mass

Amount of substance

Time

Temperature

Length

Current

What is the difference between Reading and Measurement ?

reading: A single value taken from an instrument (e.g., looking at where spot A lines up on the ruler).

Measurement: The final calculated value, which often requires finding the difference between two readings (e.g., Distance a = Reading at B — Reading at A)