NEET Revision Notes
Physics
Oscillations
Oscillatory or Vibratory motion:
Oscillatory motion is that motion in which a body moves to and fro or back and forth
repeatedly about a fixed point (called mean position), in a definite interval of time.
In such a motion, the body is confined within well-defined limits (called extreme
positions) on either side of the mean position. Thus a periodic and bounded motion
of a body about a fixed point is called an oscillatory or vibratory motion.
Types of Motion:
Periodic motion:
When a body or a moving particle repeats its motion along a definite path after
regular intervals of time, its motion is said to be Periodic Motion, and the interval of
time is called time or harmonic motion period (T). The path of periodic motion may
be linear, circular, elliptical, or any other curve.
Oscillatory motion:
To and Fro' type of motion is called an Oscillatory Motion. It need not be periodic
and need not have fixed extreme positions. The force/torque acting in oscillatory
motion (directed towards the equilibrium point) is called restoring force/torque.
Simple harmonic motion (SHM):
Simple harmonic motion is the motion in which the restoring force is proportional
to the displacement from the mean position and opposes its increase.
Class XI Physics www.vedantu.com 1
, Image: Simple harmonic motion
Simple harmonic motion (SHM):
A particle is said to move in SHM if its acceleration is proportional to the
displacement and is always directed towards the mean position
Conditions of Simple Harmonic Motion:
For SHM to occur, three conditions must be satisfied.
● There must be a position of stable equilibrium
At the stable equilibrium potential energy is minimum.
dU d 2U
So, 0 And 0
dx dy 2
● There must be no dissipation of energy.
● The acceleration is proportional to the displacement and opposite in direction,
that is a 2 y
Image: Conditions for simple harmonic motion
Class XI Physics www.vedantu.com 2
Physics
Oscillations
Oscillatory or Vibratory motion:
Oscillatory motion is that motion in which a body moves to and fro or back and forth
repeatedly about a fixed point (called mean position), in a definite interval of time.
In such a motion, the body is confined within well-defined limits (called extreme
positions) on either side of the mean position. Thus a periodic and bounded motion
of a body about a fixed point is called an oscillatory or vibratory motion.
Types of Motion:
Periodic motion:
When a body or a moving particle repeats its motion along a definite path after
regular intervals of time, its motion is said to be Periodic Motion, and the interval of
time is called time or harmonic motion period (T). The path of periodic motion may
be linear, circular, elliptical, or any other curve.
Oscillatory motion:
To and Fro' type of motion is called an Oscillatory Motion. It need not be periodic
and need not have fixed extreme positions. The force/torque acting in oscillatory
motion (directed towards the equilibrium point) is called restoring force/torque.
Simple harmonic motion (SHM):
Simple harmonic motion is the motion in which the restoring force is proportional
to the displacement from the mean position and opposes its increase.
Class XI Physics www.vedantu.com 1
, Image: Simple harmonic motion
Simple harmonic motion (SHM):
A particle is said to move in SHM if its acceleration is proportional to the
displacement and is always directed towards the mean position
Conditions of Simple Harmonic Motion:
For SHM to occur, three conditions must be satisfied.
● There must be a position of stable equilibrium
At the stable equilibrium potential energy is minimum.
dU d 2U
So, 0 And 0
dx dy 2
● There must be no dissipation of energy.
● The acceleration is proportional to the displacement and opposite in direction,
that is a 2 y
Image: Conditions for simple harmonic motion
Class XI Physics www.vedantu.com 2
