Physics Prelim 1 Flashcards
What is Physics?
Physics is a branch of Physical Science concerned with the nature and properties of matter and energy.
The subject matter of physics includes…
mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.
What is chemistry?
Chemistry is also one of the branches of Physical Science which deals with the properties, composition and structure of substances, the transformations they undergo, and the energy that is released or absorbed during these processes.
Its is defined as the process of comparing an unknown quantity to a standard.
Measurement
What are the two quantities?
fundamental quantity and derived quantity
What is a fundamental quantity?
determined directly by using a measuring device
Examples of fundamental quantity
length, mass, time, temperature, luminous intensity, electric current, and amount of substance.
What is a derived quantity?
A combination of fundamental quantities
Example of derived quantities?
area, volume, density, velocity, acceleration, force, work, power and energy.
Most of these quantities cannot be directly obtained using a_____________but all of these are combination of two or more fundamental quantities.
measuring device
What are the other quantities?
measured and exact quantities
what is the difference between measured quantity and exact quantities?
are those that can be obtained by a system of measurement while the exact quantities are those that can be counted
Examples of exact quantities
are the number of students in a class, the number of male and female passengers in a bus, number of eggs in a tray, and so on
if you have a measurement of 2.54 cm is the length of the bolt to be used, 1.05 mm diameter of a hole to be drilled.
READ 3 TIMES AND ANSWER WHAT EXAMPLE IS THIS
measured quantity
What is matter?
- the foundation or building blocks for any discussion of physics and chemistry
- it is what all things are made of, whatever occupies space, has mass, and is perceptible to the senses in some way
- it cannot be created or destroyed, but it is possible to change its physical state
the matter is composed of?
atoms
what are the tiny particles of matter?
atoms
atoms are composed of sub: particles
protons, electrons and neutrons
What is an element represent?
group of atoms
what is a molecule?
a combination of one type of element or different elements
what is mass?
is a measure of the quantity of matter or substance in an object
It does not change regardless of where you take it in the universe and it does not change with a change of state because it is about how many protons, neutrons, and electrons are in the substance. The only way to change the ___ of an object is to add or take away its atoms.
mass
The natural unit for mass
is the mass of a proton or neutron.
what is an amu?
special name of the mass natural unit which means atomic mass unit (amu)
In the English system, the standard unit of mass is
slug.
is one kind of force. It is defined as the gravitational pull of the earth on a given body.
weight
The direction of this force is toward the geometrical center of the earth. The more mass an object has, the more it will weigh under the earth’s force of gravity
weight
Mathematically, weight and mass can be stated as follows with their units in SI and English Systems:
Weight (N) = Mass (kg) x Gravity (m/s2) ,
W(dyne) = mass (g) x ag (cm/s2)
Mass (slug) = Weight (lb) ÷ Acceleration due to gravity (ft/s2)
What is attraction?
It is the force acting mutually between particles of matter, tending to draw them together, which Sir Isaac Newton called the “Law of Universal Gravitation.”
Sir Isaac Newton called it the “Law of Universal Gravitation.” He showed how each particle of matter attracts every other particle, how people are bound to the earth, and how the planets are attracted in the solar system.
attraction
What is porosity?
This means having pores or spaces where smaller particles may fit when a mixture takes place,
sometimes referred to a s granular where it consists or appears to consists of small grains or granules.
porosity
what is Impenetrability?
This means that no two objects can occupy the same place or space at the same time.
Thus, two portions of matter cannot at the same time occupy the same space.
Impenetrability
What is density?
It is defined as the mass of a sample of the material divided by the volume of the same sample.
What is the symbol used for density?
The symbol used for density is the Greek letter rho, (ρ).
Mathematically, density is expressed as follows:
Density = mass/volume, ρ = m/V.
READ
To find the density of the substance, the weight or mass and its volume must be known. The density of water at 4°C is usually used as the standard for comparing densities of other substances. The density of water is 1 g/cm3. The standard temperature of 4°C is used when measuring the density of liquids and solids because it will affect the volume of these substances at those states by expansion or contraction but not its weight or mass thus, changing its weight per unit volume. For gases, the standard conditions for the measurement of the densities have been established at 0° C for temperature and a pressure of 76 cmHg, which is the average pressure of the atmosphere at sea level. So, density is computed based on these conditions for all gases.
Density is a very important and useful concept because you can use it to find the mass or volume of a given substance or material and no two substances has the same density. So, we can easily determine the kind of substance present through its density.
the _______ is calculated by comparing the weight of a definite volume of the given substance with the weight of an equal volume of water. The terms “specific weight” or “specific density” are sometimes used to express this ratio. It is not expressed in units, but as pure numbers.
specific gravity
what is specific gravity?
It is often necessary to compare the density of one substance with another
The following formulas are used to find the specific gravity of liquids and solids.
( two formulas )
Specific Gravity = Weight of the substance/Weight of an equal volume of water
Specific gravity = Density of the substance/ Density of water
TRUE/FALSE
The same formulas are used to find the density of gases by substituting water with air or hydrogen.
TRUE
TRUE/FALSE
There are different formulas are used to find the density of gases by substituting water with air or hydrogen.
FALSE
TRUE/FALSE
Both specific gravity and density are independent of the size of the sample under consideration and depend only upon the substance of which it is made
TRUE
A device used for measuring specific gravity
hydrometer
a tubular glass float contained in a larger glass tube
hydrometer
What is force?
is described as any push or pull. It is one kind of vector and is always in a certain direction
The units in which force are measured are the…
in terms of englisg system, metric system and cgs of the metric system.
pound (lb) in the English system and the newton (N) in the metric system and dyne in the cgs of the metric system.
What is pressure?
is defined as the force divided by the area on which the force acts
The equation that defines pressure is:
P = F/A
READ
Molecules of gases are in ceaseless motion and they collide and rebound from any solid surface which they encounter. These collisions result in a net push or force on the surface creating pressure.
pressure
The metric unit of pressure is
N/m2 (newton per square meter)
This pressure (1 N/m2) has been name the ____ (Pa) in honor of the French scientist and mathematician, _____ ,The ____ is a very small unit of pressure.
pascal, blaise pascal, pascal
Read
The English unit of pressure is the lb/ft2 or the lb/in2(PSI). Another unit is the atmosphere (atm) which is equal to 14.7 lb/in2.
pressure
We live under a blanket of air on our earth. The density of air decreases with altitude. At sea level, the average atmospheric pressure is 14.7 lb/in2.
atmospheric pressure
Various types of _______ are used to measure atmospheric pressure.
barometers
READ
All the pressure measuring instruments which the airplane mechanic is likely to use are designed to register the extent to which the pressure being measured differs from the ambient pressure.
Absolute and Gage Pressures
refers to the pressure in the area immediately surrounding the object under study.
ambient pressure
The actual pressure the gas is exerting on the walls of its container is called
absolute pressure
The general relation which connects gage pressure, absolute pressure and atmospheric pressure is:
Pabs = Pg + Patm
TRUE/ FALSE
The zero on the absolute pressure scale is the pressure exerted by a perfect vacuum.
TRUE
Our common notion of hot and cold has its precise expression in the concept of
temperature
As objects are heated their molecules move faster. In a solid, molecules vibrate more rapidly. In liquids and gases, the molecules move all over in the container at a faster rate of speed. These vibrations in speed of the molecules cause objects to expand when are heated.
temperature
READ
The Fahrenheit scale (F), where the freezing point of water is 32° and its boiling point is 212°. The metric scale, Celsius (C), the freezing point of water is zero and boiling point is 100°.
temperature
TRUE/FALSE
Absolute zero is a limiting temperature that can be reached
Absolute zero is a limiting temperature which can never be reached
standard unit of length
meter (m)
standard unit of mass
kilogram (kg)
standard unit of time
seconds (s)
standard unit of temperature
kelvin (K)
standard unit of luminous intensity
candella (cd)
standard unit of electric current
ampere (A)
standard unit of amount of substance
mole (mol)
is defined as exactly 0.9144 metres so it is effectively one of the fundamental Imperial units of measurement.
yard (yd)
is a US customary unit of volume equal to a quarter of a gallon
quarts (qt)
is 1,760 yards or 5,280 feet. In 1959, by international agreement, one mile was standardized as exactly 1,609.344 metres.
mile (mi)
amu
atomic mass unit
To change the units of physical quantities, we use the technique called chain-link conversion method. It multiplies the original measurement by the conversion factor that is the ratio of units that is equal to 1
conversin of units
. For example, if we want to convert between minutes and seconds, we use the conversion factor
1min/60s= 1 or 60s/1min=1
