Measurements and Standards

Textbook of Physics for Grade 9 - Study Notes

• Textbook designed for Grade 9 physics in Sindh, Pakistan.
• Prepared by the Association For Academic Quality (AFAQ) for Sindh Textbook Board.
• Approved for secondary school examinations.

Physical Quantities and Measurement

• Physics explores nature, representing it mathematically and concluding with experiment.
• Physics deals with the behavior and structure Matter; and Matter, energy, space, time, energy, and force.
• Physicists are categorized as theoretical physicists and experimental physicists.
• Theoretical physicists present theories with mathematical approach
• Experimental physicists test them with experiments.

Main Branches of Physic

• Mechanics: It is concerned with motion, laws and gravitation.
• Thermodynamics: It deals with heat, temperature and their is relation to energy and work,
• Electricity: It is a study of the properties of charges in rest and motion
• Magnetism: Is the study of the magnetic properties of materials
• Atomic physics: It deals with the composition, structure and properties of the atom.

Other Branches of Physics

• Optics: It studies physical aspects of light and its properties with optical instruments.
• Sound: Deals with the production, properties, and applications of sound waves.
• Nuclear physics: Governs the constituents, structure, behavior, and interactions of atomic nuclei.
• Particle physics: It explores the elementary constituents of matter, radiation, and their interactions.
• Astrophysics: The physical laws help in studying celestial objects.
• Plasma physics: The study of ionized matter and its properties
• Geophysics: It explores earth’s internal structure.

Importance of Physics in Science, Technology, and Society

• Relies on technology, developed through scientific discoveries.

Measuring Instruments

• Physical quantities are important for describing the natural world.
• A physical quantity is a physical property quantified by measurement.
• Physical quantities: combination of magnitude and a unit.

Fundamental vs. derived quantities:

• Fundamental cannot be explained by other quantities.
• Derived are explained by fundamental quantities.
• There are 7 fundamental quantities

Fundamental Quantities and SI Units

Length: meter (m)
Mass: kilogram (kg)
Time: second (s)
Electric current: ampere (A)
Temperature: kelvin (K)
Amount of substance: mole (mol)
Luminous intensity: candela (cd)
Some physical qualities, like the elastic modulus, plane angle, and solid angle, don't have units

Derived Quantities and SI Units; physical qualities explained on the basis of basis of units

Volume: cubic meter (m³)
Velocity: meter per second (m/s)
Force: newton (N)
Density: kilogram per cubic meter (kg/m³)
Acceleration: meter per second squared (m/s²)
All physical quantities are either calculated mathematically or measured through an instrumen

Standard of Length

• Defined as the minimum distance between two points on the same plane.
• Meter (m): The SI unit of length.
• Defined as the distance that light travels in a vacuum in 1⁄299,792,458 of a second..
• Instruments for measuring length: meter rule and inch tape.
• Use of every instrument is restricted by smallest measurement that it can perform which is called least count.

Units of Length

1000 m = 1 km 100 cm = 1 m 1 cm = 10 mm 1 inch = 2.53 cm 12 inch = 1ft 1 yard = 3 ft

Meter Rule

• Used to measure the length of different objects. has
• Length of 1m is equal to 100 cm.
• Can measure up to 1 mm as smallest reading..

Vernier Caliper

• A precision instrument for accurately measuring internal and external distances.
• It often has both an imperial and metric scale for measurement.

Reading a Vernier Caliper

• Step 1: Place the object between the jaws of the Vernier caliper..
• Step 2: Note the main scale reading by counting lines before the zero line of Vernier scale.
• Step 3: Count the next line of Vernier scale after zero coinciding main scale.
• Step 4: Add the two reading for total.

Micrometer Screw Gauge

• Used for precision measurements in engineering.
• Used for measuring small dimensions.
• Can measure dimensions smaller than measure by a Vernier.
• Amplifies screw rotations.

Reading Micrometer Screw Gauge

• Step 1: Turn the thimble until the anvil and the spindle gently grip the object. Then Turn the ratchet until it starts to click..
• Step 2: Take the main scale reading at the edge of the thimble.
• Step 3: Take the thimble scale reading opposite the datum line of the main scale. Multiply this reading with least count (i.e., 0.01mm).
• Step 4: Now add main scale reading to thimble reading. This will be the diameter of the object.

The Standard of Mass

• Kilogram: SI unit of mass.
• Originally defined as cube of water mass at max density.
• Redefined by the International Metric Convention in 1875 using the International Prototype Kilogram.
• The mass standard is composed of special alloy cylinder dimensions 39 x 39 mm.
• Prototype Meter and Kilogram: each country subscribed to convention was assigned standards.

Additional Mass Units

1000 g = 1 kg 1 g = 1000 mg 1 g = 1000000 µg 1 g = 1000000000 ng 1 g = 0.002 lb

The Physical Balance

Instrument for measuring mass, mostly used in labs. It works on the principle of moments

The Electronic Balance

The digital mass meter uses integrated circuits. Based on balancing forces.

The Standard of Time-Time

The earth's rotation varies and so is not a a good way to measure time Second: defined as 9,192,631,770 times the period of vibration of radiation from cesium atom.

The Stop Watch and Human Time perception

Stopwatch: measures time intervals. Human reaction time: the time it takes for someone to act when needed. Typical human reaction time is time between 0.3 and 0.5 s.

Light Gates

Often used for accurate measurements of intervals of time.

Prefixes

• Used to express very large or very tiny amounts.
• Is a specifier, to indicate fractions or multiples of units.

Prefixes and Multipliers

• Tera (T) x 10^12

• Giga (G) x 10^9

• Mega (M) x 10^6

• Kilo (k) x 10^3

• Hecto (h) x 10^2

• Deka (da) x 10

• Deci (d) x 10^-1

• Centi (c) x 10^-2

• Milli (m) x 10^-3

• Micro (µ) x 10^-6

• Nano (n) x 10^-9

• Pico (p) x 10^-12

• Femto (f) x 10^-15

• Atto (a) x 10^-18

Scientific Notation:

A very simple method for notation. Uses simple numbers and powers to calculate easily.

Component Of SN

• Coefficient Must be equal to not zero but greater than one
• Base Must be ten.
• Exponent Can be positive or negative.

Density and Volume

Three Phases of matter are gas, solid, liquid.

Solid

Retains shape and size.

Liquid

• No fixed shape, It takes on its shape from a container.
• Hardly compressible.

Gas

Lacks fix shape and volume Enlarges to fill whole container.

How to measure objects/matter, including volume

• Woods float on surface because iron is denser.
• Use Cylinders and beakers to measure volume.
• Keep meniscus with eye level.

Density Equation

The measurement of mass in a volume. p= m/v Measured in kilograms or kg/m^3, or kgm^-3

Other Ways to look at density equation

mass of a substance can be expressed as: m=pV

Relation of Density's

relative density = density of substance/density of water

Significant Figures

Numbers are estimated as representing a large or small magnitude of a physical quantity. Engineers work with the accuracy of a value. Scientists are concerned about estimations.

KINEMATICS

How bodies changes position in space relative to a time interval. Disregarding any cause. The study of bodies without a reference.

SLO For Kinematrics

• Describe with examples how objects can be at rest.
• Identify motion types, including translatory, rotatory, and vibratory motions.
• Distinguish distance, displacement, velocity and acceleration.
• Determine graph attributes and shapes, to then Solve problems related to uniformly accelerated motion using appropriate techniques.
• Then solve problems related to freely falling bodies.

Introduction to Kinematics

The branch related to object motion in physics is referred to as Mechanics. Kinematics is divided into two parts. (i) Kinematics (ii) Dynamics

Kinematics is The Mechanics branch dealing with movement of objects without regard to force.

Key Rest and Motion Aspects

A body is said to be in rest if it does not change its position with respect to its surroundings. A body is said to be in motion if it changes its position with respect to its surroundings. No body in the universe is perfectly still, or in motion. Rest and Motion are all relative.

Motion Types

(i) Translatory motion - linear, circular and random (ii) Rotatory motion (iii) Vibratory motion.

Explaining Translatory Motion

Different objects are moving, and can be observed with change. When all points of a moving body move uniformly along the same straight line, such motion is called translatory motion. Motion of a body along a straight line is called linear motion. Motion of a body along a circular path is called circular motion. Irregular motion of an object is called random motion.

Explaining Rotatory and Vibratory Motion

The rotor and the body moves around a fixed axis which passes through it - spin or rotatory motion.

When swing moves away from the mean point back and forth --vibratory or oscillatory motion.

Quantities: Describing Motion

Including position, change in position, change in speed and acceleration.

Distance and Displacement

1. Difference between distance and displacement can can be differentiated due to whether its scalar or vector.
2. Total Length - Distance v. Distance.
3. Measured in a particular line or vector quantity.
4. Its SI Unit is Metre m.

More Motion Factors

Average speed of an object can calculated with:

Speed = Distance Travelled / Time Taken. Distance covered by object at speed: Average speed is unit of time.

Speed and Velocity

For a rate of change of displacement for time, its speed and velocity. Calculated based on moving object, its time, time taken,SI Unit is ms/.

• Uniform velocity if body covers equal distance at certain point.

Key aspects of acceleration

An item speeds up once pace adjustments. Hence pace is a vector quantity Produced when? Velocity of object changes; Direction of the object changes, Speed or direction of object changes The Rate of pace over Time. Accelearation is the Change in velocity/time taken,

• The acceleration is metre/second- (ms²)
• The increase generates a positive acceleration, means acceleration happens direction of the velocity.

Two Kinds of Acceleration

• Deceleration The Opposite to change velocity, such as slowing down.

Uniform Acceleration

Body, with uniform acceleration, if the velocity of body changes by an equal amount in every equal time period.

Formulas for Motion:

v= u +at. distance = ut + (1/2) x a t². v² = u² + 2as.

Scalars and Vectors

On the basis of Information you must divide Physical Quantities, which is complete. They can be Scalars or Vectors:

Scalars: Scalar Quantities can be described through Magnitude with suitable Unit

• Speed, Temp and Mass of object

The physical quantities that have magnitude and a suitable unit are called scalar quantities.

Vectors: Needs particular direction:

• Vectors are specified by direction.
• Example Bys Travelling North is an example of Description of vector quantity

the physical quantities which are completely specified by magnitude with suitable unit and particular direction are called as "Vector” quantities.

Vectors examples are momentum, force, ,acceleration.

Representation of Vector & Graph types

You can demonstrate an vector in an easy way but direct any line can specify a vector.

• The size of any line section gives Magnitude to any vector and arrow gives direction of the arrow.

Speed and Chart Reading

gradient is numerically- equal at speed.

Time-Speed

• You can see how much speed increases at amount every second you can get at speed-amount.

Any object is zero, then a diagram is created and you get acceleration in movement of objects.

Therefore positive slope will mean is acceleration is negative.

Laws of Motion.

• Newton's Laws of Motion: Every thing will be uniform at its line unless external pressure makes it change from it
• Momentum of Force Rate of Change equal or force and you can follow its times

DYNAMICS

• Study of motion causes, where common force is cause or motion.
• Also studied are Factors like mass, the object and frictional force also affect the motion of an object are also studied under dynamics.

SLO For Dynamics

• Define momentum, then understand, utilize principle with collisions. This includes identifying safety with changing momentum.
• Describe Newton's laws, while being able to distinguish between mass and weight in problems. Have the ability to explain forces acting on body, compute force, define friction, identify relation to load and friction.
• Further demonstrate less force is needed with sliding friction

Key Aspects of Momentum

If ball and car are moving at equal speed and car stops earlier, it depends on the mass and velocity of object at the particular time. The bigger the mass the more momentum.

More Aspects

The momentum of an object is measured by the object's mass and depends of: Momentum = force x velocity(3.1) Where the vector unit becomes force and acceleration are vector components.

Types of Momentum/ Force

If equal force is a must on various objects. Newton Second Law explains relation between movement & relation.

How Momentum is defined.

That is a momentum equals rate or force x per time.

Ap= FT........................................................3(3.2)

Device aspects

There important steps of using any device Cars should have safety measures to protect you, such as car parts. Helmets should protect from direct strike on head.

Newtons Law's

Concept of Energy

Mainly import in specific events or is a key calculation The point: [after system collision] is all dependent and same.

The total momentum of an isolated system always remains constant"

Simplicy & System For Collison. It depends on what the type is like of collisions and masses

First Law Of Motion

Continues to move in Straight line unless external power changes. What is called inertia. Meaning an object will resist the rate of change

How Interia is defined

Describes force requirements: The inertia is the property

2nd and 3rd Laws

Newton was able to classify what happens with various type of power.

when a net force acts on a body it produces acceleration in the direction of force. The acceleration is directly proportional to force and inversely proportional to mass of body".

3rd Lae To every action, there will be equal power

• Significant Figures* Quantifies digits that are reliably recognised. The known figures reliably in the range is important as its explained in significant figures-

Rules Of SN

All - NON zeros must be present in it The Leading zeros must not included, because the system must have more Trapped must take place, or is already happening, so it can count (0.00509 ) A number can only be added with SN. With an exponent to add the values.

PROPERTIES OF MATTER SLOS

Students needs an introduction to heat, then they can move with Kinetic model. This will provide an understanding of various parts of an everyday activity.

Key Topics For Property SLO

• Describing States of matter is very important for all things, heat related. Matter can exist on three phases such as SOLID GAS & LIQUID.
• State Kinetic Molecular Model which is useful to distinguish all parts of an system.
• The main concept is, The Heat is a transfer of energy it’s a transfer of energy, then explain force and how it connects.

MATTER IN PHYSICS

Matter is made up of tiny particles called atoms, these "particles" can be solid, gas, or plasma in state. There changes also are caused under specific conditions.

• Evaporation
• Melting
• Boiling Those which have different amounts of energy or force.

SLO For Dynamics

• You can create the description of the object depending on all its changes of energy
• Describe kinetic molecular model of matter to provide useful info.
• The heat model should touch each component to help students better explain and differentiate all phases and components/actions that are happening.

FORCES AND KINETIC THEORY

Some substances solids and liquids, others are gas under same conditions? Its how the forces is spread, the states have molecules to help. If the amount of energy are not balanced.

• KINETIC MODEL- This creates forces of tractation when the matter has lots of power, helps the the bodies stick closer and have strong properties .

Key Components

With different states: It can convert ice or cream. And some will need more of cooling and head for certain states:

For example can occur under specific heat is put the change in pressure:

These components will then act as base items.

• Also with temperature if higher or lower to be balanced, its how a gas increases in a system - a system has some sort of equation for the heat that needs to be used
• A change in a state of matter is caused by adding or withdrawing a certain amount of energy.

THERMAL SLO

• Distinguishing with temperature is important because you need to define both - You must explain the the state of energy for all three phases. (LIQUID Gas & Plasma) & You should
• Also List some factors for them while defining them - You can
• Check on why there needs to be heat to be transfer depending on components or the matter

Components and Phases

• Thermometre & all its values which differ
• HEAT with S.I Unit joule, can also can depend under other units Depending on the level of heat you can then decide if what occurs, which depends on what happens.

Example of Thermometer and heat

• If the rate were to change, then if you could increase and find that it can effect things - you will then to find out some info, which means one of the states will get bigger and give off more energy.

Heat equation

That will take on a different state

• the change heat will come together to give you certain type of heat

Kinetic Theory of Gas

A change in the state with these models for better info. For Kinetic Theory , 7 important points are needed: the the relationship or its heat. What happens is you can then list or do what is needed.

• Boiling: you take them into the boiling point or get all important stuff

These models will get the student everything needed at their level.

This quiz covers measurement errors with tools like micrometer screw gauges, the definition and history of the kilogram, and unit conversions between pounds, grams, milligrams, micrograms, and nanograms. It also explores old standards of density and the copies of international standards.