Units that are basic like meters, seconds, and kg
Units that are made up of multiple fundamental units like velocity which is m/s
Looking at what dimensions aka [length], [time], [mass] are in an equation, and see if they are all the same or cancel out.
Just a number.
Time, mass, energy work, power, temp, pressure.
A number with a direction.
Displacement, velocity, acc, force, momentum, torque.
Numbers that matter, AKA anything that can’t be removed in scientific notation.
Addition and Subtraction:
The answer will have the same amount of decimals as the number with the LOWEST amount of decimals.
2.347 + 1.56 = 3.907 = 3.91
Multiplication and Division:
The answer will have the same amount of sig-figs as the number with the LOWEST amount of sig-figs
2.347 * 1.56 = 3.66132 = 3.66
(Conversion factors NEVER change num of sig-figs)
How close the measured values are to the TRUE value
How close are the measured values to each other, like are they all similar, or are they very different.
ALSO how reproducible it is.
The instrument is miscalibrated or the entire experiment is just wrong
You get the right answer, but each measured value is completely different.
The plain uncertainty that you get is like “dA = 0.1 m”.
This can be good for some things, but not for others, like 0.1m is good for the height of skyscrapers, but NOT for surgery.
Relative Uncertainty (percentage):
The relative percentage of what the measurement is, like how much does it stray from the actual value.
Low = Good
High = Bad
The First Condition for Equilibrium:
The net external forces on the SYSTEM must be 0, so both in x and y directions.
Something where there is NO motion
Something where the velocity of the system is CONSTANT, AKA just moved by inertia
The Second Condition for Equilibrium:
There must be NO change in rotational motion, so either NO motion or CONSTANT motion.
This means that the net TORQUE is 0