What is a physical quantity
Property of an object that can be measured, represented by a mangnitude and unit
What are basic quantities
Fundamental physcial quantites that cannot be defined in terms of other quantites
What are derived quantites
Formed by combining base quantites
What is the prefix, symbol and standard form for
1) Nanometer
2) Mircometer
3)Milimeter
Nanometer
Prefix: nano
Symbol: n
Standard form:10^-9
Micrometer
Prefix: micro
Symbol: µm
Standard form:10^-6
Prefix: milli
Symbol: mm
Standard form= 10^-3
What is the prefix, symbol and standard form for
4) centi
5) deci
6) kilo
Prefix: centi
Symbol: cm
Standard form:10^-2
Prefix: deci
Symbol: dm
Standard form:10^-1
Prefix: kilo
Symbol: km
Standard form:10^3
What is the prefix, symbol and standard form for
7) mega
8) giga
Prefix: mega
Symbol: Mm
Standard form:10^6
Prefix: giga
Symbol: Gm
Standard form:10^9
What is precision
The smallest unit an instrument can measure
What is the zero error
When a measuring instrument does not read zero when it should, so all measurements are too big or too small by the same amount.
What is accuary
How close a measured value is to the true (actual) value.
Difference between precision and accuracy
Accuracy = correct value
Precision = consistency
Example:
If your measurements are all very similar but far from the true value → precise but not accurate
If your measurements are close to the true value but spread out → accurate but not precise
How can you measure time effectively using a stopwatch?
1) Start and stop the stopwatch carefully to reduce reaction time error
2) Repeat measurements and take an average
3)Avoid measuring very short time intervals
How do you measure the period of a pendulum accurately?
1) Measure time for many swings (e.g. 10–20 oscillations)
2) Divide total time by number of swings
3) Measure from the same point each time (e.g. middle to middle)
4) Keep the swing angle small
Repeat and take an average
What experimental errors can occur in a pendulum experiment?
1)Air resistance slows the pendulum
2)Friction at the pivot affects motion
3)Not measuring from the same reference point each time
pt 2 pendalum
4)Using too large an angle changes motion
5) Timing too few swings increases percentage error
What errors can occur when using a stopwatch in experiments?
1)Starting or stopping slightly late/early
2)Inconsistent timing between repeats
3) Random timing mistakes due to human delay
