Introduction to Physics and their Measurements Flashcards
What is Physics
A branch of science which uses experiments, measurements and maths to create laws which describe everything in the universe.
What do Physics Laws describe?
Energy and matter and how they relate to each other
What are some forms of energy?
Light, motion, gravity, electricity and radiation
What is matter?
Matter is everything. It covers tiny atoms, sub atomic particles al the way to large structures like stars and galaxies
What are the two areas of physics?
Theoretical and Experimental
Describe experimental Physics.
- Create a hypothesis. 2. Test the hypothesis with an experiment. 3. Observe results. 4. Conclusion and establish new scientific law.
Describe theoretical physics.
Theoretical physics describes the results of experimental data and observation using maths and other scientific concepts.
How does Physics relate to chemistry?
Chemistry deals with the interactions of atoms and molecules so it is rooted in atomic and molecular physics.
How does Physics relate to architecture?
Physics is the heart of structural stability and is involved in the heating, lighting and cooling of buildings.
How does physics relate to geology?
We use physics in earthquake analysis, radioactive dating of rocks and heat transfer in earth.
What is a Quantity?
An amount, a measurement of something and its unit.
What is the unit for length, area and volume?
Length: metres (m), Area: square meters (m^2) , Volume: cubic metres (m^3)
What is the unit for Time, mass and speed?
Time: Seconds (s), Mass: Kilograms (kg), Speed: metres/second (m/s)
What is the unit for Energy, Electrical Charge, Resistance?
Energy: Joules (J), Electrical charge: Coloumbs (C) Resistance: Ohms
What is a significant figure?
The most important digits which convey meaning according to its accuracy.
What are the SI units?
System International Units, a system of measurements agreed upon by scientist all over the world.
What are base units?
The fundamental units which all other units are derived.
How many base units are there? What are these?
- Mass, length, time, temperature, electrical current, amount of substance.
What are the units of the six base units?
Mass (kilogram), Length (metre), Time(seconds), Temperature (Kelvin), Electrical Current (Ampere), Amount of substance (mol)
What is a derived quantity?
These are types of measurements that a gotten from base units.
What is the unit and symbol for force, pressure, workdone, power, potential difference, Electrical Resistance and electrical Charge?
Force (Newton/N), Pressure (Pascals/Pa), Work done(Joule/J), Power(Watt/W), Potential difference(Volt/V), Electrical Resistance (Ohm/Ω) and Electrical Charge (Coulumb/C)
What are the equations and alternative unit for Force, Pressure, Work done, Power, Potential difference, Electrical Resistance, and Electrical Charge.
Force (mass x acceleration) (kgms-1), Pressure (force/area)(Nm-2), Work done(Force x distance)(Nm), Power (Energy/time)(Js-1), Potential difference(Energy/Charge)(JC-1), Electrical Resistance (Voltage/Current)(VA-1) and Electrical Charge (Current x time)(AS)
What is a mistake?
A mistake is when you do something incorrectly. For example measuring the wrong way or using the wrong procedure?
How can we fix mistakes?
By repeating our procedure in the right way.
What is an error?
The difference between a measured value and the true value of the quantity being measured. All measurements have errors.
What is random error?
- Affects precision
- Cannot be corrected or removed
- Take repeated measurements of the values.
What is systematic error?
-Affects accuracy
-Due to measurement tools or external factors such as the time and place
- Will throw off the value by the same amount each time
What is accuracy?
A measure of how close your experimental measurements agree with the known values.
What is precision?
A measure of how close your experimental measurements agree with each other.
What is Absolute Uncertainty?
mean +/- (range/2) Half the range of measurements in the mean value
What are fractional and percentage uncertainty?
Uncertainty is given in percentage and fraction format. The equation is absolute uncertainty/mean value.
When is Uncertainty combined?
During addition and subtraction, the uncertainty of both measurements is combined.
Why is it incorrect to think that the more digits you represent in your answer, the more accurate it is?
The number of digits you present in your answer should represent the precision with which you know a measurement; it says very little about the accuracy of the measurement. For example, if you measure the length of a table to great precision, but with a measuring instrument that is not adjusted correctly, you will not measure accurately.
