This is Dipraj Roy from Department of Geology and Mining , University of Barishal. I was prepared a slide on requested of Dr. Rahima Nasrin Ma'am ,Assistant Professor , Department of Physics, University Of Barishal.

1. Oscillatory
Motions
P R ESENTED BY
D I P RAJ ROY
RO L L - 1 9 GLM016
D E PARTMENT O F G EO LOGY A ND M I NI NG
UN I VERSI TY O F BARI SHAL

2. Outline
 Simple Harmonic Motion;
 Damped Harmonic Motion;
 Forced Oscillation
 Resonance

3. What is oscillatory motion?
Oscillatory motion is defined as the TO
and FRO motion of an object from its
mean position.

4. Simple Harmonic Motion
Simple harmonic motion can be described as an oscillatory motion in which the acceleration of
the particle at any position is directly proportional to the displacement from the mean position.
Two Types
Linear SHM Angular SHM
a = -ω2 x.
Linear SHM:- When a particle moves to and fro about a fixed point along with a straight line then its motion called linear simple harmonic
motion
Example: Spring-mass system
Angular SHM:- When a system oscillates angular long with respect to a fixed axis then its motion called angular simple harmonic motion.
Example:- Physical Pendulam
Here, ω is the angular velocity of the particle

5. Damped Simple Harmonic Motion
A simple harmonic motion whose amplitude
goes on decreasing with time is known as
damped harmonic motion. the motion of an
oscillator reduces due to an external force or
restoring force or frictional force, the
oscillator and its motion are damped
𝒅2𝒙/ 𝒅𝒕2 +ϒ𝒅𝒙/𝒅𝒕+𝝎2𝒙=0
Differential equation of damped harmonic motion

6. Forced oscillation
When a body oscillates by being
influenced by an external periodic
force, it is called forced oscillation.
Here, the amplitude of oscillation,
experiences damping but remains
constant due to the external energy
supplied to the system.

7. Resonance
A phenomenon in which an
external force or a vibrating
system forces another system
around it to vibrate with greater
amplitude at a specified
frequency of operation. Frequencies at which
the response amplitude
is a relative maximum
are also known as
resonant frequencies
or resonance
frequencies of the
system
Examples:Musical Instruments , Swing , Bridge,