|
Force
|
Power
|
|
|
Definition
|
A push or a pull resulting from an
interaction between objects.
|
Power is the rate at which work is
done, or energy is transmitted.
|
|
Unit
|
newton
|
watt = joules/second
|
|
Symbol
|
F
|
P
|
|
Named
After
|
Isaac Newton
|
James Watt
|
|
Derivations
from other quantities
|
F = m a (force = mass multiplied
by acceleration)
|
P = w/t (power = work divided by
time)
|
|
Relation
to “Work”
|
Force applied over a distance
creates work.
|
Rate at which work is performed.
|
|
Everyday
Example
|
Gravity, friction, magnetism.
|
Horsepower (1 horsepower = 750
Watts).
|
|
Power
|
And Torque
|
|
|
Definition
|
Power is the rate at which work is
done, or energy is transmitted.
|
Torque is the tendency of a force
to rotate an object about an axis (or fulcrum or pivot). Just as a force is a
push or a pull, a torque can be thought of as a twist. The symbol for torque
is τ, the Greek letter tau.
|
|
Unit
|
watt = joules/second
|
Newton meter or joules per radian
|
|
Energy
|
Power
|
|
|
Definition
|
Energy is the capacity to do work.
Energy is power integrated over time.
|
Power is the rate at which work is
done, or energy is transmitted.
|
|
Unit
|
joules = watt-seconds
|
watt = joules/second
|
|
Common
symbol(s)
|
W
|
P
|
|
Example
|
My car's battery can provide 500
amps at 12 volts, which equals 6kW of power.
|
Comparison chart
|
Speed
|
Velocity
|
|
|
Nature
|
Scalar
|
Vector
|
|
Calculated
with
|
Distance
|
Displacement
|
|
Components
|
Distance, time
|
Distance, time and direction of
motion
|
|
Average
|
Distance/time
|
Displacement/time
|
|
Mass
|
Weight
|
|
|
Definition
|
Mass is the quantity of matter in
a body regardless of its volume or of any forces acting on it.
|
Weight is a measurement of the
gravitational force acting on an object.
|
|
Effect
of gravity
|
Mass is always constant at any
place and any time
|
The weight of an object depends on
the gravity at that place
|
|
Measurement
Unit
|
Mass is expressed in kilogram
(kg), grams (g), and milligram (mg).
|
Weight is expressed in Newton (N)
|
|
Balance
used for measurement
|
Mass is measured using a pan
balance, a triple-beam balance, lever balance or electronic balance.
|
Weight is measured using a spring
balance.
|
|
Type
of Quantity
|
Scalar and base quantity
|
Vector and derived quantity
|
|
Heat
|
And
Temperature
|
|
|
Definition
|
Heat is energy that is transferred
from one body to another as the result of a difference in temperature.
|
Temperature is a measure of
hotness or coldness expressed in terms of any of several arbitrary scales
like Celsius and Fahrenheit.
|
|
Symbol
|
Q
|
T
|
|
Unit
|
Joules
|
Kelvin, Celsius or Fahrenheit
|
|
SI
unit
|
Joule
|
Kelvin
|
|
Particles
|
Heat is a measure of how many
atoms there are in a substance multiplied by how much energy each atom
possesses.
|
Temperature is related to how fast
the atoms within a substance are moving. The ‘temperature’ of an object is
like the water level – it determines the direction in which ‘heat’ will flow.
|
|
Ability
to do work
|
Heat has the ability to do work.
|
Temperature can only be used to
measure the degree of heat.
|
Comparison chart
Celsius |
Kelvin |
|
|
Absolute
zero
|
-273.15
|
0.00
|
|
Average
human body temperature
|
37.0
|
309.95
|
|
Boiling
temperature for water (at standard pressure)
|
99.9839
|
373.1339
|
|
Surface
of the Sun
|
5526
|
5800
|
|
Highest
recorded surface temperature on the Earth
|
58
|
331
|
|
Lowest
recorded surface temperature on the Earth
|
-89
|
184
|
|
Melting
temperature for ice (at standard pressure)
|
0
|
273.14
|
Comparison chart
Science |
Technology |
|
|
Motto
|
Science is knowing.
|
Technology is doing
|
|
Mission
|
The search for and theorizing
about cause
|
The search for and theorizing
about new processes.
|
|
Result
Relevance
|
Making virtually value-free
statements
|
Activities always value-laden
|
|
Evaluation
Methods
|
Analysis, generalization and
creation of theories
|
Analysis and synthesis of
design
|
|
Goals
achieved through
|
Corresponding Scientific
Processes
|
Key Technological Processes
|
|
Focus
|
Focuses on understanding
natural phenomena
|
focuses on understanding the
made environment
|
|
Development
Methods
|
Discovery (controlled by
experimentation)
|
Design, invention, production
|
|
Most
observed quality
|
Drawing correct conclusions based
on good theories and accurate data
|
Taking good decisions based on
incomplete data and approximate models
|
|
Skills
needed to excel
|
Experimental and logical skills
|
Design, construction, testing,
planning, quality
assurance, problem solving, decision making, interpersonal and
communication skills
|
|
Kinetic Energy
|
Potential Energy
|
|
|
Definition
|
The energy of a body or a system
with respect to the motion of the body or of the particles in the system.
|
Potential Energy is the stored
energy in an object or system because of its position or configuration.
|
|
Relation
to environment
|
Kinetic energy of an object is
relative to other moving and stationary objects in its immediate environment.
|
Potential energy is not relative
to the environment of an object.
|
|
Transferability
|
Kinetic energy can be transferred
from one moving object to another, say, in collisions.
|
Potential energy cannot be
transferred.
|
|
Examples
|
Flowing water, such as when
falling from a waterfall.
|
Water at the top of a waterfall,
before the precipice.
|
|
SI
Unit
|
Joule (J)
|
Joule (J)
|
|
Determining
factors
|
Speed/velocity and mass
|
Height or distance and mass
|
Comparison chart
Acceleration |
Velocity |
|
|
Nature
|
Vector
|
Vector
|
|
Calculated
with
|
Velocity
|
Displacement
|
|
Components
|
Velocity, time
|
Distance, time and direction of
motion
|
|
Average
|
Velocity/time
|
Displacement/time
|
|
Unit
|
m/s2
|
m/s
|
|
Equation
|
a=v/t
|
v=d/t
|
|
Electric Field
|
Magnetic Field
|
|
|
Nature
|
Created around electric charge
|
Created around moving electric
charge and magnets
|
|
Units
|
Newton per coulomb, volts per
meter
|
Gauss or Tesla
|
|
Force
|
Proportional to the electric
charge
|
Proportional to charge and speed
of electric charge
|
|
Movement
In Electromagnetic field
|
Perpendicular to the magnetic
field
|
Perpendicular to the electric
field
|
|
Electromagnetic
Field
|
Generates VARS (Capacitive)
|
Absorbs VARS (Inductive)
|
|
Pole
|
Monopole or Dipole
|
Dipole
|
Comparison chart
Current |
Voltage |
|
|
Definition
|
Current is the rate at which
electric charge flows past a point in a circuit. In other words, current is
the rate of flow of electric charge.
|
Voltage, also called
electromotive force, is the potential difference in charge between two points
in an electrical field. In other words, voltage is the "energy per unit
charge”.
|
|
Symbol
|
I
|
V
|
|
Unit
|
A or amps or amperage
|
V or volts or voltage
|
|
SI
Unit
|
1 ampere =1 coulomb/second.
|
1 volt = 1 joule/coulomb.
(V=W/C)
|
|
Measuring
Instrument
|
Ammeter
|
Voltmeter
|
|
Relationship
|
Current is the effect (voltage
being the cause). Current cannot flow without Voltage.
|
Voltage is the cause and
current is its effect. Voltage can exist without current.
|
|
Field
created
|
A magnetic field
|
An electrostatic field
|
|
In
series connection
|
Current is the same through all
components connected in series.
|
Voltage gets distributed over
components connected in series.
|
|
In
a parallel connection
|
Current gets distributed over
components connected in parallel.
|
Voltages are the same across
all components connected in parallel.
|
Comparison chart
Centrifugal Force |
Centripetal Force |
|
|
Meaning
|
Tendency of an object following
a curved path to fly away from the center of curvature. Might be described as
“lack of centripetal force.”
|
The force that keeps an object
moving with a uniform speed along a circular path.
|
|
Direction
|
Along the radius of the circle,
from the center towards the object.
|
Along the radius of the circle,
from the object towards the center.
|
|
Example
|
Mud flying off a tire; children
pushed out on a roundabout.
|
Satellite orbiting a planet
|
|
Formula
|
Fc = mv2/r
|
Fc = mv2/r
|
|
Defined
by
|
Chistiaan Hygens in 1659
|
Isaac Newton in 1684
|
|
Is
it a real force?
|
No; centrifugal force is the
inertia of motion.
|
Yes; centripetal force keeps
the object from "flying out".
|
Comparison chart
Alternating Current |
Direct Current |
|
|
Amount
of energy that can be carried
|
Safe to transfer over longer
city distances and can provide more power.
|
Voltage of DC cannot travel
very far until it begins to lose energy.
|
|
Cause
of the direction of flow of electrons
|
Rotating magnet along the wire.
|
Steady magnetism along the
wire.
|
|
Frequency
|
The frequency of alternating
current is 50Hz or 60Hz depending upon the country.
|
The frequency of direct current
is zero.
|
|
Direction
|
It reverses its direction while
flowing in a circuit.
|
It flows in one direction in
the circuit.
|
|
Current
|
It is the current of magnitude
varying with time
|
It is the current of constant
magnitude.
|
|
Flow
of Electrons
|
Electrons keep switching directions
- forward and backward.
|
Electrons move steadily in one
direction or 'forward'.
|
|
Obtained
from
|
A.C Generator and mains.
|
Cell or Battery.
|
|
Passive
Parameters
|
Impedance.
|
Resistance only
|
|
Power
Factor
|
Lies between 0 & 1.
|
it is always 1.
|
|
Types
|
Sinusoidal, Trapezoidal,
Triangular, Square.
|
Pure and pulsating.
|
Comparison chart
Li-ion |
NiCad |
|
|
Nominal
cell voltage
|
3.6 / 3.7 V
|
1.2 V
|
|
Cycle
durability
|
400-1200 cycles
|
2,000 cycles
|
|
Specific
power
|
~250-~340 W/kg
|
150 W/kg
|
|
Charge
/ discharge efficiency
|
80-90%
|
70–90%
|
|
Self-discharge
rate
|
8% at 21 °C, 15% at 40 °C, 31%
at 60 °C (per month)
|
10% per month
|
|
Energy
density
|
250-620 W•h/L
|
50–150 W•h/L
|
|
Specific
energy
|
100-250 W•h/kg
|
40–60 W•h/kg
|
|
Disposal
|
Non-hazardous waste
|
Hazardous waste
|
|
Maintenance
|
Does not need periodic
discharge
|
Requires full discharge before
recharge
|
|
Weight
|
20%-35% less than Nicad
|
more
|
|
Memory
effect
|
Do not suffer from memory
effect
|
Suffer from memory effect
|
|
Nuclear Fission
|
Nuclear Fusion
|
|
|
Definition
|
Fission is the splitting of a large
atom into two or more smaller ones.
|
Fusion is the fusing of two or
more lighter atoms into a larger one.
|
|
Natural
occurrence of the process
|
Fission reaction does not normally
occur in nature.
|
Fusion occurs in stars, such as
the sun.
|
|
Byproducts
of the reaction
|
Fission produces many highly
radioactive particles.
|
Few radioactive particles are
produced by fusion reaction, but if a fission "trigger" is used,
radioactive particles will result from that.
|
|
Conditions
|
Critical mass of the substance and
high-speed neutrons are required.
|
High density, high temperature
environment is required.
|
|
Energy
Requirement
|
Takes little energy to split two
atoms in a fission reaction.
|
Extremely high energy is required
to bring two or more protons close enough that nuclear forces overcome their
electrostatic repulsion.
|
|
Energy
Released
|
The energy released by fission is
a million times greater than that released in chemical reactions, but lower
than the energy released by nuclear fusion.
|
|
|
Nuclear
weapon
|
One class of nuclear weapon is a
fission bomb, also known as an atomic bomb or atom bomb.
|
One class of nuclear weapon is the
hydrogen bomb, which uses a fission reaction to "trigger" a fusion
reaction.
|
|
Energy
production
|
Fission is used in nuclear power
plants.
|
Fusion is an experimental
technology for producing power.
|
|
Fuel
|
Uranium is the primary fuel used in
power plants.
|
Hydrogen isotopes (Deuterium and
Tritium) are the primary fuel used in experimental fusion power plants.
|
|
Endothermic
|
Exothermic
|
|
|
Introduction
|
A process or reaction in which the
system absorbs energy from its surroundings in the form of heat.
|
A process or reaction that
releases energy from the system, usually in the form of heat.
|
|
Result
|
Energy is
absorbed from the environment into the reaction.
|
Energy is released from the system
into the environment.
|
|
Form
of Energy
|
Energy is absorbed as heat.
|
|
|
Application
|
Thermodynamics; physics,
chemistry.
|
Thermodynamics; physics,
chemistry.
|
|
Etymology
|
Greek words endo (inside) and
thermasi (to heat).
|
Greek words exo (outside) and
thermasi (to heat).
|
|
Examples
|
Melting ice, photosynthesis,
evaporation, cooking an egg, splitting a gas molecule.
|
Explosions, making ice, rusting
iron, concrete settling, chemical bonds, nuclear fission and fusion.
|
|
Absorption
|
Adsorption
|
|
|
Definition
|
Assimilation of molecular species
throughout the bulk of the solid or liquid is termed as absorption.
|
Accumulation of the molecular
species at the surface rather than in the bulk of the solid or liquid is
termed as adsorption.
|
|
Phenomenon
|
It is a bulk phenomenon
|
It is a surface phenomenon.
|
|
Heat
exchange
|
Endothermic
process
|
Exothermic
process
|
|
Temperature
|
It is not affected by temperature
|
It is favoured by low temperature
|
|
Rate
of reaction
|
It occurs at a uniform rate.
|
It steadily increases and reach to
equilibrium
|
|
Concentration
|
It is same throughout the
material.
|
Concentration on the surface of
adsorbent is different from that in the bulk
|
|
Diffusion
|
Osmosis
|
|
|
What
is it?
|
Diffusion is a spontaneous
movement of particles from an area of high concentration to an area of low
concentration. (ex. tea flavoring moving from an area of high to low
concentration in hot water.)
|
Osmosis is the spontaneous net
movement of water across a semipermeable membrane from a region of low solute
concentration to a solution with a high solute concentration, down a solute
concentration gradient.
|
|
Process
|
Diffusion mainly occurs in gaseous
state or within gas molecules and liquid molecules.(e.g. The molecules of 2
gases are in constant motion and if the membrane separating them is removed
the gases will mix because of random velocities.)
|
It occurs when the medium
surrounding the cell has a higher water concentration than the cell. The cell
gains water along with important molecules and particles for growth. It also
occurs when water and particles move from one cell to another.
|
|
Importance
|
In animals, osmosis influences the
distribution of nutrients and the release of metabolic waste products. In
plants, osmosis is partially responsible for the absorption of soil water and
for the elevation of the liquid to the leaves of the plant.
|
|
|
Concentration
Gradient
|
Goes from a high concentration
gradient to a low concentration gradient
|
Moves down concentration gradient
|
|
Water
|
Doesn’t need water for movement
|
Needs water for movement
|
|
Examples
|
Perfume or Air Freshener where the
gas molecules diffuse into the air spreading the aroma.
|
Movement of water into root hair
cells.
|
Comparison chart
Hard Water |
Soft Water |
|
|
Contains
|
Minerals such as calcium and
magnesium
|
Sodium
|
|
Reaction
with soap
|
Film
|
Suds
|
|
Problems
|
Leaves deposit called “scale”
|
None
|
|
Lather
formation
|
Doesn't form lather with
detergents
|
Forms lather with detergents
|
|
Removed
by
|
permutit process, by exchange
of ions
|
none
|
|
Acid
|
Base
|
|
|
Definition
|
Arrhenius Definition: An acid is
any chemical compound which when dissolved in water gives a solution with a
hydrogen ion activity greater than in pure water. Bronstead Lowry Definition:
An acid is an substance which donates a proton.
|
Arrhenius Definition: A base is an
aqueous substance that can accept hydrogen ions. Bronstead Lowry Definition:
A base is any substance which accepts a proton.
|
|
pH
(measure of concentration of hydrogen ions in a solution)
|
Less than 7.0.
|
Greater than 7.0 and could go up
to 14 in case of stronger bases.
|
|
Physical
characteristics
|
Depending on the temperature,
acids can occur in solid, liquid or gaseous form. Taste sour.
|
Bases feel slippery because of the
reaction of the base with the oils of your hand. Frequently solids except
ammonia which is a gas. Taste bitter.
|
|
Strength
|
depends on concentration of the
hydronium ions
|
depends on concentration of the
hydroxide ions
|
|
Phenolphthalein
|
remains colorless
|
Makes it pink
|
|
Other
Properties
|
Electrolytes, conduct electricity
(because electrolytes), react with many metals.
|
Electrolytes, conduct electricity,
ranges from insoluble to so soluble that they can react with water vapor.
|
|
Dissociation
|
Acids free hydrogen ions (H+) when
mixed with water.
|
Bases free hydroxide ions (OH-)
when mixed with water.
|
|
Chemical
Formula
|
An acid has a chemical formula
with H at the beginning of it. For example, HCl (Hydrochloric Acid). There is
one exception to his rule, CH3COOH = Acetic Acid (vinegar)
|
A base has a chemical formula with
OH at the end of it. For example, NaOH (Sodium Hydroxide).
|
|
Examples
|
Acetic acid i.e.CH3COOH and
Sulfuric acid
|
Sodium Hydroxide (NAOH) and
Ammonia (NH3)
|
|
Litmus
test
|
Acids change litmus paper red.
|
Bases change litmus paper blue.
|
Relative
humidity of 30 to 50% is recommended for good health. This
is challenging in extreme conditions such as dry heat or too much moisture. A humidifier is used to increase the level of humidity in the air
and a dehumidifier reduces the humidity level of the air. A hygrometer can be used to measure the humidity of a particular
area to decide whether a humidifier or dehumidifier is required.
Dehumidifier Humidifier
|
Purpose
|
To reduce the moisture content in
the surrounding area.
|
To increase the moisture content
in the surrounding area.
|
|
Usage
|
During warm/humid climate in
either a single room or basement or the entire house.
|
During winter or when the air is
cold and dry in either a single room or the entire house.
|
|
Application
|
Recommended to alleviate allergy
by eliminating mold, dust mites and mildew from the air.
|
Suitable to moisten dry skin and
nasal passages that dry up due to common cold.
Humidifier works best in children’s room.
|
|
Humidity
levels
|
Used where humidity is greater
than 50%
|
Used where humidity is less than
35%
|
|
Types
|
Mechanical /refrigerative, Air
conditioners, Adsorption/desiccant, Electronic, Ionic membrane, Makeshift
|
Warm mist and cool mist
|
No comments:
Post a Comment