Oscillatory Motion

Types of Motion Transitional motion Periodic motion

Periodic Motion It is the motion which is regularly repeated in equal period of time

Types of Periodic Motion Wave motion Oscillatory motion

The Concept of Oscillatory Motion

The Concept of Oscillatory Motion Observation: The oscillating body moves on both sides around its original position (A). This motion is repeated in equal period of time. The displacement of the oscillating body around its original position are equal. The velocity of the oscillating body reaches its maximum value when it passes its original position and decreases gradually when it goes far from it

Oscillatory motion It is the motion of the oscillating body around its rest point, where the motion is repeated in equal period of time.

Question The following figure represent an oscillatory motion for a simple pendulum. The maximum velocity of the pendulum is at point(s)………..(A/B/C/C, B). The velocity decreases at point(s)………..(A/B/C/B, C)

Graphical Representation of The Oscillatory Motion:

Concept of OscillatoryMotion amplitude Complete oscillation Periodic time frequency

Amplitude The maximum displacement on the right side at point (B). The maximum displacement on the left side at point (C).

Amplitude It is the maximum displacement done by the oscillating body away from its original position. The measuring unit of the amplitude is meter “m” or centimeter “cm”.

What is meant by? The amplitude of an oscillating body is 2 cm. This means that maximum displacement of the oscillating body away from its original position is 2 cm.

Complete Oscillation A → B → A → C → A. It is the motion of an oscillating body when it passes by a fixed point on its path two successive times in the same direction.

Complete Oscillation The complete oscillatory movement include 4 displacements (four amplitudes). AB – BA – AC – CA.

Exercise In which graph, the amplitude is larger? The amplitude of curve (1) is larger than the amplitude of curve (2). How many complete oscilations do exist between the points x and y represented on both graphs? In curve (1): 3 In curve (2): 4

Periodic Time It is the time taken by an oscillating body to make one complete oscillation. The measuring unit of periodic time is second “sec”

Periodic Time (T) The periodic time = time in seconds number of complete oscillations The periodic time of an oscillating body which makes 240 oscillations in one minute equals…………….. 1 4 sec

What is meant by? The periodic time of an oscillating body is 0.2 seconds. this means that the time taken by this oscillating body to make one complete oscillation is 0.2 second.

Frequency (F) It is the number of complete oscillation made by an oscillating body in one second. The measuring unit of frequency is Hertz “Hz”

Frequency (F) Kilohertz= 103 HZ Megahertz= 106 HZ Gigahertz= 109HZ

Frequency (F) The frequency= number of complete oscillations time in seconds A simple pendulum makes 540 complete oscillations in a minute, so its frequency is……….. 9 Hz.

The Relation Between Frequency and Periodic Time Frequency (F) x Periodic time (T)= 1 Frequency (F)= 1 T Periodic time(T)= 1 F

Proplem Calculate the periodic time and frequency for an oscillating body that makes 300 complete oscillations in half a minute. t= 0.5 x 60 =30 sec. T= t(sec) no.of complete oscillation T= 30 = 0.1 sec 300 F= 1 = 1 = 10 Hz T 0.1

REAL LIFE APPLICATION MICROWAVE OVEN

Quiz

A-COMPLETE: 1-………...motion and……..motion are 2 types of periodic motion. 2-The complete oscillation includes…….successive displacements, each of them is called………. B-G.R: The oscillatory motion is considered as periodic motion. C- problem: If the frequency of an oscillating body is 10 HZ, find: 1- its periodic time 2- the time taken to make 300 complete oscillations. 3- the number of complete oscillations this body makes in a minute.