DEFINITIONS Flashcards
It is a disturbance in a medium that carries energy without a net movement of particles. It may take the form of elastic deformation, a variation of pressure, electric or magnetic intensity, electric potential, or temperature.
Waves
It is a motion in which all points on a wave oscillate along paths at right angles to the direction of the wave’s advance.
Transverse Wave
Ripples on the surface of water
Transverse wave
Vibrations in a guitar string
Transverse wave
A Mexican wave in a sports stadium
Transverse wave
Electromagnetic waves - e.g. light waves, microwaves, radio waves.
Transverse wave
Seismic S-waves
Transverse wave
Are waves where the displacement of the medium is in the same direction as the direction of the travelling wave.
Longitudinal Waves
Sound Waves in air
Longitudinal wave
The primary waves of an earthquake
Longitudinal wave
Ultrasound
Longitudinal wave
The vibration of a spring
Longitudinal wave
The fluctuations in a gas
Longitudinal wave
The tsunami waves
Longitudinal waves
It is the maximum displacement of any particle in the medium relative to its position.
Amplitude (A)
______ of vibration is the time for a particle to complete one cycle
Period (T)
_____ of vibration is the number of such vibrations executed by the particle each second
Frequency (f)
It is the distance along the direction of propagation between corresponding points on the wave.
Wavelength (λ) - Lambda symbol
The frequency of a vibrating string is inversely proportional to the length when other factors are considered the same
f1/f2 = L2/L1
Law of length
The frequency of a vibrating string is directly proportional to the square root of the tension when other factors are considered the same.
f1/f2 = squareroot of T1/T2
Law of Tension
The frequency of a vibrating string is inversely proportional to its diameter when the other factors are considered the same
f1/f2 = d1/d2
Law of Diameter
The frequency of a vibrating string is directly proportional to the square root of the density when other factors are considered the same
f1/f2 = squareroot p1/p2
Law of Density
v = f * λ
Wavelength formula
It is the pattern of disturbance caused by the movement of energy traveling through a medium( such as air, water or any other liquid or solid matter) as it propagates away from the source of the sound,
Sound wave
Nature of waves
Infrasonic wave
Sonic wave
Ultrasonic wave
Are waves whose frequencies are too low for human to hear.
These have frequencies below 20Hz
Infrasonic Waves
In order to generate ___, these three important thing must be present.
1. There must be a vibrating body
2. There must be a medium to transmit the vibration (It can’t travel in vacuum)
3. There must be a receiver to detect the it.
sound
Are waves that can be heard by human ear.
Frequency range: 20Hz to 20,000 Hz
Sonic Waves
Are Waves whose frequencies are too high to hear.
These have the frequencies greater than 20,000Hz
Ultrasonic Waves
In order to generate sound, these three important thing must be present.
- vibrating body
- a medium
- a receiver
Classification of Sound
Tones or Musical Sounds
Noise
A sound of one regular vibration or one being received by the ear to have musical sequence.
Tones or Musical Sounds
A sound of irregular vibration or one with no definite range of frequency.
Noise
Characteristics of Sound
Loudness
Pitch
Quality or Timbre
Intensity
Is a physiological sensation that refers to the strength of the sensation as received by the ear. It depends mainly on the sound amplitude of vibrations. Its subjected unis is SONE
Loudness
Is the attribute of auditory sensation in terms of which sound may be ordered on a scale primarily related to frequency. Its subjected unit is MEL.
Pitch
Is the attribute of auditory sensation in terms of which a listener can judge that two sounds similarly presented and having he same loudness and pitch are dissimilar. It is also known as “Tone color”.
Quality or Timbre
Is the power carried by the wave through a unit area perpendicular to the direction of propagation of the vibrating body.
Intensity
Sound Terminologies (RESSBR)
Echo
Reverberation
Shock Wave
Sonic Boom
Beats
Resonance
Is a reflected sound. Sound like light waves can be reflected back when strikes a surface.
Echo
Is the persistence of sound in space after the original sound is removed.
Reverberation
Is the cone-shaped wave made by an object moving at supersonic speed through a fluid
Shock wave
Refers the the alternation of maximum and minimum sound intensity produced by super position of two sound waves of slightly different frequencies.
Beats
Is the loud sound resulting from the incidence of a shock wave
Sonic Boom
Refers to the response of a body when a forcing frequency matches its natural frequency.
Resonance
Sound Terminologies (MINN)
Natural Frequencies
Noisiness
Interference
Mach Number (M)
refers to the unwantedness of sounds. The subjected to unit of it is NOY.
Noisiness
Is the superimposition of one wave on another
Interference
Is a frequency at which an elastic object naturally tends to vibrate if its disturbed and the disturbing force is removed.
Natural frequencies
Is the speed of an object moving through air, or any fluid substance, divided by the speed of sound as it is in that substance. It was provided by the Austrian Physicist Emst Mach.
Mach Number (M)
Mach Number (M)
Is the speed of an object moving through air, or any fluid substance, divided by the speed of sound as it is in that substance. It was provided by whom?
Austrian Physicist Emst Mach
Subsonic
M<1
Sonic
M=1
Transonic
0.8<M<1.2
Supersonic
1.2<M<5
Hypersonic
M>5
Is the apparent rise and falls in the pitch of t he sound of a sounding body as the sounding body or observer approaches or leaves the observer.
fo = fs(v+-vo/v+-vs)
Doppler effect
the material expands in the direction of the applied force
Tensile stress
The modulus of elasticity is define as the ratio of:
stress–strain
The Bernoulli’s equation is derived from the conservation of
Energy
The pressure in a fluid at rest varies with
depth
Ohm’s Law states that the current through a conductor between two points is directly proportional to the
voltage (V)
In a series circuit, the total resistance is equal to
The sum of the individual resistances
Which of the following is true for a parallel circuit?
a. The total voltage is the sum of the voltages across each component
b. The total resistance is the sum of the individual resistances
c. The total current is the sum of the currents through each component
d. The total power is the product of the power of each component.
c. The total current is the sum of the currents through each component.
The unit of electrical power is
watt (W).
In a capacitor, the opposition to the change in voltage is called
capacitance
s of water
1.0
Y of water
9.81 kN/m^3 (62.4 lb/ft^3)
p of water
1000kg/m^3 (1.94 slugs/ft^3)
What is the magnitude of the resultant force of the two forces which are perpendicular to each other? The two forces are 20 units and 30 units respectively
36
The resultant of two forces in a plane is 400N at 120 degrees. If one of the forces is 200 N at 20 degrees what is the other force?
477.27N at 144.38 Degrees
(477.16 N and a direction of approximately 144.21 degrees)
Determine the resultant of the following forces: A = 600N at 40 degrees, B = 800 N at 160 degrees and C= 200 N at 300 degrees
532.78 N, 55.32 degrees
What is the branch of engineering mechanics which refers to the study of stationary rigid body?
Statistics
What is the branch of engineering mechanics which refers to the study of rigid body in motion under the action of forces?
dynamics
What refers to the force that holds part of the rigid body together?
Internal force
A ball is shot vertically into the air at a velocity of 193.2 ft per sec (58.9 m per sec). After 4 sec, another ball is shot vertically into the air. What initial velocity must the second ball have in order to meet the first ball 386.4 ft (117.8 m) from the ground?
158.67 ft/s
Energy cannot be transformed. T or F?
False
Energy can neither be created nor destroyed. T or F?
True
An object is travelling at a velocity of 10m/s. It has a mass of 2 kg. It impacts a spring of spring constant “k” as shown in the figure. What is the compression of the spring?
10 square root of 2/k or 10(2/k)^0.5
The law of conservation of energy is not applicable to mechanical systems as they require energy input to keep working
False
The potential energy of an object maximizes as its velocity increases
False
A 10kg object is raised to a height of 20m. What is the magnitude of its potential energy? Assume g = 10m/s
2000J
Find the ration of potential energy if an object is raised to thrice of its height and its mass is tripled
1:9
Two bodies moving with constant velocities collide with each other. Which of the following quantities remain conserved?
Momentum
Which law is also called as the elasticity law?
Hooke’s Law
Two bodies of masses 2kg and 7kg are moving with velocities of 2m/s and 7m/s respectively. What is the total momentum of the system in kg-m/s
53
The upper part of the peak of the wave
Crest
The bottom peak of the wave
Trough
Measure of the wave starting at the middle
Amplitude
Combination of upper and lower portions of the wave
Cycle
Length of the wave
Wavelength
Minimum power for hearing is equivalent to?
Wo = 1 x 10^-12 W
Velocity of sound in the air Celsius
Tc < 20degree Celsius (V = 331.45 +06Tc)
Minimum intensity for hearing is equivalent to?
Io = 1 x 10^-12 W/m^2
Speed of sound in the air Kelvin
V = 331.45 square root Tk/273
Comes from the Greek therme, meaning “heat” and dynamis, meaning “power”.
Thermodynamics
Thermodynamics Comes from the Greek word
therme, meaning “heat” and dynamis, meaning “power”.
It is the science that deals with the conversion of energy
from one form to another, the direction of heat, and the
availability of the energy to do work.
THERMODYNAMICS
system refers to a definite
quantity of matter most
often contained with
some closed surface
chosen for study.
Thermodynamic
Energy->System<-Matter
Isolated System
Energy<–>System<–Matter
Closed System
Energy<–>System<–>Matter
Open System
Are properties that do not depend on the mass of the system such as temperature, pressure, density and velocity.
Intensive Properties
Are properties that depend on the mass of the system such as volume, momentum and kinetic energy.
Extensive Properties
Properties of a System
Intensive Properties and Extensive Properties
It refers to a state of balance. Under this condition, there are no unbalanced
potentials or driving forces within the system.
Equilibrium (Thermodynamics Equilibrium)
a state wherein the temperature is the same all throughout the entire system.
Thermal Equilibrium
A state wherein the phase of the system involving two or more pase stays the same
at a point in time.
Phase Equilibrium
Kinds of Thermodynamics Equilibrium
Thermal Equilibrium, Mechanical Equilibrium, and Phase Equilibrium
A state wherein there is no change in pressure at any point of the system with time.
Mechanical Equilibrium
a state wherein the temperature is the same all throughout the entire system.
Thermal Equilibrium
A state wherein there is no change in pressure at any point of the system with time.
Mechanical Equilibrium
A state wherein the phase of the system involving two or more pase stays the same
at a point in time.
Phase Equilibrium
Is used to measure the degree of hotness and coldness of a thermodynamic
substance with reference to a standard value. It is measured using the device
called Thermometer.
Temperature
Is the temperature at which the substance changes its state from solid to liquid. If
the substance is liquid at 25, this temperature is usually called the freezing point.
Melting point
Is the temperature at which the substance changes its state from liquid to gas. If
the substance is gas at 25, this temperature is usually called condensation point.
Boiling Point
Is a point on a three dimensional graph of temperature, pressure and
molar volume beyond which that substance can only exist gas.
Critical point
Is the point (combination of temperature and pressure) at which all
three phases of that substance coexist simultaneously.
Triple point
Temperature
Triple point and Critical point
Celsius Scale (named after Swedish astronomer,
Anders Celsius)
In this scale, the boiling point and the freezing point
of water at STP (Standard Temperature and
Pressure) is
Celsius Scale (named after Swedish astronomer,
Anders Celsius)
Fahrenheit Scale (named after German Physicist
Gabriel Daniel Fahrenheit)
the boiling point of water at
standard atmospheric pressure is 212 and the freezing
point is .
Fahrenheit Scale (32 F)
Kelvin (named after British scientist Lord Kelvin also known as ___ ___ ___ who first used the term
thermodynamics).
Sir William Thomson
Rankine (named after ____ who wrote the first thermodynamic textbook)
William Macquorn Rankine
It is the absolute temperature scale. This standard is
based on the triple point of water 273.16 K.
Kelvin (named after British scientist Lord Kelvin also
known as Sir William Thomson who first used the term
thermodynamics).
Transfer of energy between adjacent molecules
Conduction
is a form of transferred energy
between two bodies that
arises from the random
motion of molecules.
Heat Energy or Thermal Energy
Movement of hot fluid
Convection
Emission of electro magnetic rays
Radiation
Is the amount of heat necessary to change the temperature of the system without changing its phase.
Sensible Heat
Is the amount of heat necessary to change the phase of a system without
changing its temperature.
Latent Heat
Total heat entering the substance is the sum of the latent heat and the sensible heat.
Total Heat
is the amount of heat required to change
the temperature of one gram of a substance by .
Specific Heat
- What does the term “thermodynamics”
originate from?
A) Greek words “therme” and “dynamis”
B) Latin words “thermus” and “dynamis”
C) Greek words “thermo” and “dynamic”
D) Latin words “thermo” and “dynamic”
A) Greek words “therme” and “dynamis”
- Which of the following is an intensive
property?
A) Volume
B) Kinetic energy
C) Temperature
D) Momentum
C) Temperature
- Which device is used to measure temperature?
A) Barometer
B) Hygrometer
C) Thermometer
D) Anemometer
C) Thermometer
- What is the temperature at which a substance
changes from liquid to gas called?
A) Melting point
B) Freezing point
C) Boiling point
D) Condensation point
C) Boiling point
- At what point do all three phases of a
substance coexist?
A) Melting point
B) Boiling point
C) Triple point
D) Critical point
C) Triple point
- Which temperature scale is based on the triple
point of water at 273.16 K?
A) Celsius
B) Fahrenheit
C) Kelvin
D) Rankine
C) Kelvin
MPa
N/mm^2
Pa
N/m^2
dry friction formula
f=uN
Rectilinear Motion
Vf = Vi + at
d = Vit + 1/2 at^2
Vf^2 = Vi^2 + 2ad
Kinetic Energy
KE = 1/2 mv^2
Gravitational Potential Energy
GPE = mgh
spring constant
k = F/x(distance stretched)
