Mechanics II : Pressure, Oscillations, Waves. Flashcards Preview

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Flashcards in Mechanics II : Pressure, Oscillations, Waves. Deck (63)
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1
Q

Definition of Pressure:

A

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

2
Q

SI Unit of Pressure:

A

SI Unit of Pressure: Pascal (Pa).

1 Pa = 1 N/m^2

3
Q

Other commonly used units of pressure:

add the conversion values

A

1 mmHg = 133 Pa

1 bar = 105 Pa

4
Q

What is the formula for Pressure?

A

𝑝=𝐹/𝐴

5
Q

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

A

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

6
Q

Definition of Density (𝜌):

A

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

7
Q

Formula for Density:

A

𝜌=π‘š/𝑉

8
Q

SI Unit for Density:

A

Density SI unit: kg/m3

9
Q

The density of materials depend on their temperature and ________.

A

The density of materials depend on their temperature and pressure.

10
Q

Definition of Hydrostatic pressure:

A

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

11
Q

Formula for Hydrostatic pressure:

A

p= Οβˆ™gβˆ™h

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

12
Q

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

A

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

13
Q

The standard atmospheric pressure is ___ kPa= 1 atm

A

The standard atmospheric pressure is 101 kPa = 1 atm

14
Q

The atmospheric pressure changes with _________

A

The atmospheric pressure changes with temperature

15
Q

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

A

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

16
Q

Formula for Partial Pressure:

A

π‘ƒπ‘Žπ‘Ÿπ‘‘π‘–π‘Žπ‘™ π‘π‘Ÿπ‘’π‘ π‘ π‘’π‘Ÿπ‘’=π‘Žπ‘π‘ π‘œπ‘™π‘’π‘‘π‘’ π‘π‘Ÿπ‘’π‘ π‘ π‘’π‘Ÿπ‘’ βˆ™π‘“π‘Ÿπ‘Žπ‘π‘‘π‘–π‘œπ‘› π‘œπ‘“ π‘”π‘Žπ‘ 

17
Q

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

A

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

18
Q

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

A

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

19
Q

What is an Oscillation?

A

The periodic motion around an equilibrium point.

20
Q

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

A

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

21
Q

Definition of Harmonic oscillation:

A

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

22
Q

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

A

𝑦=π΄βˆ™sin⁑(πœ”π‘‘+πœ‘0)
πœ” - angular frequency,
πœ‘0 - initial phase
A - amplitude

23
Q

What is the Point of equilibrium (In Oscillations) ?

A

Point of equilibrium: The point the system oscillates around

24
Q

What is the Displacement (In Oscillations) ?

A

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

25
Q

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

A

Amplitude (A): Maximal displacement

26
Q

What is the Period (T)?

A

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

27
Q

What is Frequency (f)? Unit?

A

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

28
Q

What is the formula for Frequency?

A

𝑓=1/𝑇

1/s = Hz

29
Q

What is Angular frequency (𝝎)?

A

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

30
Q

What is the Angular frequency (𝝎) Formula

A

πœ”=2πœ‹βˆ™π‘“

31
Q

A physical system undergoing oscillations, is called an _______

A

A physical system undergoing oscillations, is called an oscillator

32
Q

What is Hooke’s Law?

A

𝐹=βˆ’π‘˜*π‘₯
𝐹 - Elastic Force of a Spring
π‘˜ - Spring Constant (Hooke’s)
x - Displacement

33
Q

Define Simple Harmonic Oscillation, give an example as well

A

No energy loss during the motion

Classical example: Mass on a spring oscillator (Hooke’s Law)

34
Q

What is Natural frequency (also called Eigenfrequency) ?

A

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

35
Q

What is the formula for calculation of Eigenfrequency?

A

𝑓0=1/2πœ‹ √(π‘˜/π‘š)

36
Q

Definition of Damped oscillation:

A

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

37
Q

Define Driven oscillation:

A

Driven oscillation: An external force is driving the oscillation.

38
Q

What is Resonance?

A

Resonance: Vibration of a driven force together with a system

39
Q

What is the Resonance curve?

A

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

40
Q

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

A

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

41
Q

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

A

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

42
Q

What is a Wave?

A

A wave is a propagating oscillation

43
Q

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

A

1) Mechanical Waves (e.g. sound waves)

2) Electromagnetic wave (e.g. visible light, UV light)

44
Q

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

A

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

45
Q

What is a Wavelength (πœ†)? Unit?

A

Wavelength (πœ†): The distance between two points of a wave with the same phase [m]

46
Q

What is a Wave front?

A

Wave front: Surface containing points of waves in identical phases

47
Q

Propagation of a wave: What is C?

A

C is the speed of light

Which is constnat?

48
Q

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

A

𝑐= πœ†/𝑇=πœ†βˆ™1/𝑇=πœ†π‘“

from v=x/t

49
Q

What is the Huygens-Fresnel principle?

A

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

50
Q

What is a Spherical Wave?

A

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

51
Q

What is a Plane wave?

A

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

52
Q

Definition of Diffraction:

A

Diffraction: Occur when many sources of waves are present.

53
Q

Definition of Interference:

A

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

54
Q

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

A

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

55
Q

Superposition means for the resulting wave that:

A

𝑅𝑒𝑠𝑒𝑙𝑑𝑖𝑛𝑔 π‘€π‘Žπ‘£π‘’=π‘€π‘Žπ‘£π‘’1+π‘€π‘Žπ‘£π‘’2

56
Q

What types of Interference are there?

A

Can be constructive or destructive

57
Q

Definition of Polarization:

A

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

58
Q

Reflection Definition:

A

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

59
Q

Types of Reflection:

A

1) Specular Reflection

2) Diffuse Reflection

60
Q

Formula for law of reflection:

A

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

61
Q

Definition of Refraction:

A

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

62
Q

What is Snell’s Law?

A

Snell’s Law: Describes the relationship between the angle of the incidence (πœƒ1) and refractory wave (πœƒ2) when passing from one medium (𝑛1) to another medium (𝑛2).

63
Q

Formula for Snell’s Law:

A

𝑛1 *sin⁑(πœƒ1)=𝑛2 *sin⁑(πœƒ2)

𝑠𝑖𝑛(πœƒ1)/𝑠𝑖𝑛(πœƒ2 )=𝑐1/𝑐2