Mechanics II : Pressure, Oscillations, Waves.

Question 1

Definition of Pressure:

Answer 1

Pressure (p) is the force (F) applied perpendicular to a surface area (A).

Question 2

SI Unit of Pressure:

Answer 2

SI Unit of Pressure: Pascal (Pa).

1 Pa = 1 N/m^2

Question 3

Other commonly used units of pressure:

add the conversion values

Answer 3

1 mmHg = 133 Pa

1 bar = 105 Pa

Question 4

What is the formula for Pressure?

Answer 4

𝑝=𝐹/𝐴

Question 5

________ is a physical quantity with important application in physics, physiology and medical procedures. E.g. blood _______ cuff measurement

Answer 5

Pressure is a physical quantity with important application in physics, physiology and medical procedures. E.g. blood pressure cuff measurement

Question 6

Definition of Density (𝜌):

Answer 6

Density (𝜌): The mass (m) of a homogenous body divided by its volume (V)

Question 7

Formula for Density:

Answer 7

𝜌=𝑚/𝑉

Question 8

SI Unit for Density:

Answer 8

Density SI unit: kg/m3

Question 9

The density of materials depend on their temperature and ________.

Answer 9

The density of materials depend on their temperature and pressure.

Question 10

Definition of Hydrostatic pressure:

Answer 10

Hydrostatic pressure: Pressure in gases and liquids due to gravity.

Question 11

Formula for Hydrostatic pressure:

Answer 11

p= ρ∙g∙h

g is gravity constant (9.81m/s2 - precisely) and h is height (m).

Question 12

Atmospheric (barometric) pressure - It ________ exponentially with elevation.

Answer 12

Atmospheric (barometric) pressure - It decreases exponentially with elevation.

Question 13

The standard atmospheric pressure is ___ kPa= 1 atm

Answer 13

The standard atmospheric pressure is 101 kPa = 1 atm

Question 14

The atmospheric pressure changes with _________

Answer 14

The atmospheric pressure changes with temperature

Question 15

In a mixture of gases, each gas in the mixture will exert a pressure, this is called the _____ _______

Answer 15

In a mixture of gases, each gas in the mixture will exert a pressure, this is called the partial pressure

Question 16

Formula for Partial Pressure:

Answer 16

𝑃𝑎𝑟𝑡𝑖𝑎𝑙 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒=𝑎𝑏𝑠𝑜𝑙𝑢𝑡𝑒 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 ∙𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑔𝑎𝑠

Question 17

Oxygen (21%) as an example for Partial pressure at sea level:

Answer 17

Partial pressure of O2 at sea level (PO2) = 1atm21%O2(of air) = 101kPa0.21 = 21.2kPa

Question 18

The total pressure in the gas mixture is the ___ of all partial pressures

Answer 18

The total pressure in the gas mixture is the sum of all partial pressures

Question 19

What is an Oscillation?

Answer 19

The periodic motion around an equilibrium point.

Question 20

Sound in form of speech is created due to _______ of the vocal cords and hearing due to _________ of auditory ossicles.

Answer 20

Sound in form of speech is created due to oscillation of the vocal cords and hearing due to oscillation of auditory ossicles.

Question 21

Definition of Harmonic oscillation:

Answer 21

Harmonic oscillation: Restoring force is working on a system displaced out of equilibrium.

Question 22

For Harmonic Oscillation - The displacement is given as sine function of time, What is the formula?

Answer 22

𝑦=𝐴∙sin⁡(𝜔𝑡+𝜑0)
𝜔 - angular frequency,
𝜑0 - initial phase
A - amplitude

Question 23

What is the Point of equilibrium (In Oscillations) ?

Answer 23

Point of equilibrium: The point the system oscillates around

Question 24

What is the Displacement (In Oscillations) ?

Answer 24

Displacement: The movement of the oscillating object away from the equilibrium point.

Question 25

What is the Amplitude (A- In oscillations)?: Maximal displacement

Answer 25

Amplitude (A): Maximal displacement

Question 26

What is the Period (T)?

Answer 26

Period (T): Duration of one cycle (s).

Question 27

What is Frequency (f)? Unit?

Answer 27

Frequency (f): Number of cycles per unit time (1/s = Hz)

Question 28

What is the formula for Frequency?

Answer 28

𝑓=1/𝑇 | 1/s = Hz

Question 29

What is Angular frequency (𝝎)?

Answer 29

Angular frequency (𝝎) : 2𝜋 times frequency (1/s)

Question 30

What is the Angular frequency (𝝎) Formula

Answer 30

𝜔=2𝜋∙𝑓

Question 31

A physical system undergoing oscillations, is called an _______

Answer 31

A physical system undergoing oscillations, is called an oscillator

Question 32

What is Hooke's Law?

Answer 32

𝐹=−𝑘*𝑥 𝐹 - Elastic Force of a Spring 𝑘 - Spring Constant (Hooke's) x - Displacement

Question 33

Define Simple Harmonic Oscillation, give an example as well

Answer 33

No energy loss during the motion | Classical example: Mass on a spring oscillator (Hooke's Law)

Question 34

What is Natural frequency (also called Eigenfrequency) ?

Answer 34

Natural frequency (also called Eigenfrequency) is the frequency of free oscillation (spontaneous oscillation without any external stimuli).

Question 35

What is the formula for calculation of Eigenfrequency?

Answer 35

𝑓0=1/2𝜋 √(𝑘/𝑚)

Question 36

Definition of Damped oscillation:

Answer 36

Damped oscillation: Oscillations with energy loss as the time progress. Amplitude decreases with time.

Question 37

Define Driven oscillation:

Answer 37

Driven oscillation: An external force is driving the oscillation.

Question 38

What is Resonance?

Answer 38

Resonance: Vibration of a driven force together with a system

Question 39

What is the Resonance curve?

Answer 39

Resonance curve: Represent the oscillation amplitude as a function of the driving frequency.

Question 40

Resonance curve -The magnitude of resonance depends on _______ of the system

Answer 40

Resonance curve -The magnitude of resonance depends on damping of the system

Question 41

Resonance curve - In a driven system, the resonance frequency goes towards the ___________

Answer 41

Resonance curve - In a driven system, the resonance frequency goes towards the eigenfrequency

Question 42

What is a Wave?

Answer 42

A wave is a propagating oscillation

Question 43

What types of waves are there? (based on origin, with examples)

Answer 43

1) Mechanical Waves (e.g. sound waves) | 2) Electromagnetic wave (e.g. visible light, UV light)

Question 44

What types of waves are there? (direction of oscillation and propagation)

Answer 44

1) Transverse Wave : The direction of oscillation is perpendicular to the direction of propagation. 2) Longitudinal Wave : The direction of oscillation is parallel to the direction of propagation

Question 45

What is a Wavelength (𝜆)? Unit?

Answer 45

Wavelength (𝜆): The distance between two points of a wave with the same phase [m]

Question 46

What is a Wave front?

Answer 46

Wave front: Surface containing points of waves in identical phases

Question 47

Propagation of a wave: What is C?

Answer 47

C is the speed of light | Which is constnat?

Question 48

Propagation of a wave: What is the releeationship between C, the Wavelength and the frequency of the Wave?

Answer 48

𝑐= 𝜆/𝑇=𝜆∙1/𝑇=𝜆𝑓 | from v=x/t

Question 49

What is the Huygens-Fresnel principle?

Answer 49

Huygens-Fresnel principle: Concept of wave propagation. Every point of a wave-front is a source of a further wave.

Question 50

What is a Spherical Wave?

Answer 50

The waves originate from a common point, but propagate in every direction.

Question 51

What is a Plane wave?

Answer 51

Plane wave: The wave front form parallel planes to each other, but perpendicular to the direction of propagation.

Question 52

Definition of Diffraction:

Answer 52

Diffraction: Occur when many sources of waves are present.

Question 53

Definition of Interference:

Answer 53

Interference: Occur when 2 waves originating from different sources emerges and converge

Question 54

Interference - Based on Principle of _________: The resulting wave is the sum of each individual wave function

Answer 54

Interference - Based on Principle of Superposition: The resulting wave is the sum of each individual wave function

Question 55

Superposition means for the resulting wave that:

Answer 55

𝑅𝑒𝑠𝑢𝑙𝑡𝑖𝑛𝑔 𝑤𝑎𝑣𝑒=𝑤𝑎𝑣𝑒1+𝑤𝑎𝑣𝑒2

Question 56

What types of Interference are there?

Answer 56

Can be constructive or destructive

Question 57

Definition of Polarization:

Answer 57

Oscillation (i.e Light) is oriented in a preferred direction by a polarizer. Only transverse waves can be polarized

Question 58

Reflection Definition:

Answer 58

Reflection: The incident ray or part of it is returned at the interface between different media.

Question 59

Types of Reflection:

Answer 59

1) Specular Reflection | 2) Diffuse Reflection

Question 60

Formula for law of reflection:

Answer 60

Formula for law of reflection: 𝛼=𝛽 𝛼 - Incident Angle 𝛽 - Reflected Angle

Question 61

Definition of Refraction:

Answer 61

Refraction: Change of direction when an incidence wave propagates from one medium into another.

Question 62

What is Snell's Law?

Answer 62

Snell's Law: Describes the relationship between the angle of the incidence (𝜃1) and refractory wave (𝜃2) when passing from one medium (𝑛1) to another medium (𝑛2).

Question 63

Formula for Snell's Law:

Answer 63

𝑛1 *sin⁡(𝜃1)=𝑛2 *sin⁡(𝜃2) | 𝑠𝑖𝑛(𝜃1)/𝑠𝑖𝑛(𝜃2 )=𝑐1/𝑐2