Introduction to Physics and their Measurements

Question 1

What is Physics

Answer 1

A branch of science which uses experiments, measurements and maths to create laws which describe everything in the universe.

Question 2

What do Physics Laws describe?

Answer 2

Energy and matter and how they relate to each other

Question 3

What are some forms of energy?

Answer 3

Light, motion, gravity, electricity and radiation

Question 4

What is matter?

Answer 4

Matter is everything. It covers tiny atoms, sub atomic particles al the way to large structures like stars and galaxies

Question 5

What are the two areas of physics?

Answer 5

Theoretical and Experimental

Question 6

Describe experimental Physics.

Answer 6

1. Create a hypothesis. 2. Test the hypothesis with an experiment. 3. Observe results. 4. Conclusion and establish new scientific law.

Question 7

Describe theoretical physics.

Answer 7

Theoretical physics describes the results of experimental data and observation using maths and other scientific concepts.

Question 8

How does Physics relate to chemistry?

Answer 8

Chemistry deals with the interactions of atoms and molecules so it is rooted in atomic and molecular physics.

Question 9

How does Physics relate to architecture?

Answer 9

Physics is the heart of structural stability and is involved in the heating, lighting and cooling of buildings.

Question 10

How does physics relate to geology?

Answer 10

We use physics in earthquake analysis, radioactive dating of rocks and heat transfer in earth.

Question 11

What is a Quantity?

Answer 11

An amount, a measurement of something and its unit.

Question 12

What is the unit for length, area and volume?

Answer 12

Length: metres (m), Area: square meters (m^2) , Volume: cubic metres (m^3)

Question 13

What is the unit for Time, mass and speed?

Answer 13

Time: Seconds (s), Mass: Kilograms (kg), Speed: metres/second (m/s)

Question 14

What is the unit for Energy, Electrical Charge, Resistance?

Answer 14

Energy: Joules (J), Electrical charge: Coloumbs (C) Resistance: Ohms

Question 15

What is a significant figure?

Answer 15

The most important digits which convey meaning according to its accuracy.

Question 16

What are the SI units?

Answer 16

System International Units, a system of measurements agreed upon by scientist all over the world.

Question 17

What are base units?

Answer 17

The fundamental units which all other units are derived.

Question 18

How many base units are there? What are these?

Answer 18

6. Mass, length, time, temperature, electrical current, amount of substance.

Question 19

What are the units of the six base units?

Answer 19

Mass (kilogram), Length (metre), Time(seconds), Temperature (Kelvin), Electrical Current (Ampere), Amount of substance (mol)

Question 20

What is a derived quantity?

Answer 20

These are types of measurements that a gotten from base units.

Question 21

What is the unit and symbol for force, pressure, workdone, power, potential difference, Electrical Resistance and electrical Charge?

Answer 21

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)

Question 22

What are the equations and alternative unit for Force, Pressure, Work done, Power, Potential difference, Electrical Resistance, and Electrical Charge.

Answer 22

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)

Question 23

What is a mistake?

Answer 23

A mistake is when you do something incorrectly. For example measuring the wrong way or using the wrong procedure?

Question 24

How can we fix mistakes?

Answer 24

By repeating our procedure in the right way.

Question 25

What is an error?

Answer 25

The difference between a measured value and the true value of the quantity being measured. All measurements have errors.

Question 26

What is random error?

Answer 26

• Affects precision
• Cannot be corrected or removed
• Take repeated measurements of the values.

Question 27

What is systematic error?

Answer 27

-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

Question 28

What is accuracy?

Answer 28

A measure of how close your experimental measurements agree with the known values.

Question 29

What is precision?

Answer 29

A measure of how close your experimental measurements agree with each other.

Question 30

What is Absolute Uncertainty?

Answer 30

mean +/- (range/2) Half the range of measurements in the mean value

Question 31

What are fractional and percentage uncertainty?

Answer 31

Uncertainty is given in percentage and fraction format. The equation is absolute uncertainty/mean value.

Question 32

When is Uncertainty combined?

Answer 32

During addition and subtraction, the uncertainty of both measurements is combined.

Question 33

Why is it incorrect to think that the more digits you represent in your answer, the more accurate it is?

Answer 33

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.