summary for physic
Chapter One : Wave Motion
1-
The wave: It is a disturbance that propagate, spreads and carries
energy along
2- The displacement: Is the distance of an object
at any instance from its rest (equilibrium) position.
3- The
amplitude of oscillation "A"
It is the maximum
displacement, OR, is the distance between two points, along the path
of the oscillating object its velcoity is maximum at one of them, and
is zero at the other.
4- The complete oscillation:
Is the
movement of a continously of a vibrating body through the time
intrval it passes by a fixed point two successive times in the same
direction.
5- The period: "T"
- Is the time
taken by a continously vibrating body to performone complete
oscillation. OR - Is the time taken by a continously vibrating body
to pass a fixed point two successive times in the same direction.
6-
The frequency : ""
- Is the Nnumber of of complete oscillations produced by a
vibrating object in one second. It is also the number of waves
passing by a certain point in one second.
8-
Mechanical waves: - They are either
1- transverse
2-
longitudinal - Transverse wave: are that in which particles of midium
oscillate about their equilibrium position perpendicular to the
direction of propagation.
- It consists of crests and troughs.
In succession
- Its wave length is the distance between two
successive crests or troughs.
* Longitudinal wave:
- Are
that in which the particle of midum oscillate about their equilibrium
positions along the same direction of propagation.
- It
consists of compressions and rarefactions in succession .
- Its
wave length is the distance between two sucessive compressions or
rarefactions.
9- The wave length:
It
is the distance between two successive points a long the direction of
propagation of the wave where the phase is the same. (same
disoplacement and same amplitude)
10-
,
for any wave motion
Chapter Two : Sound
1-
Laws of reflection of sound:
Fisrt law: angle of incidence =
angle of reflection
- Second law: The incident sound ray, the
reflected sound ray and the normal to the reflecting surface at the
point of incidence, all lie in one plane to the reflecting surface.
2- Law of refraction of sound: -
Sound changes its direction (refracts) when traveling from one medium
to another due to variations in the velocity of sound in the two
media that:
3-
Interference of sound:
- Constructive interference:
(maximum
intensity) of equal frequency and amplitude sound waves)
- Path
difference = m
Distructive interference:
(zero intensity interference):
4-
Sound diffracts when obstructed by on obstacle or upon passage
through an aperture of dimensions comparable to tis wave length.
5-
Standing waves:
- Node: is a position of zero vibration
amplitude.
- Antinode: is a position of maximum vibration
amplitude..
- The waves length:
of
a standing wave.
It is double the distance between two
successive nodes or two successive antinodes.
5- Vibration of
strings:
-
The ratio between tones produced by a string is : 1: 2: 3: ……..
- The parameter affecting the
fundamental tone are:
