1.0 Types of Motion

  Simple Harmonic Motion

1. Periodic Motion: Periodic motion of a body is that which is repeated identically after a fixed interval of time.

Examples:

• The revolution of earth around the sun is a periodic motion. Its period of revolution is one year.

• Uniform circular motion is a periodic motion.

2. Oscillatory Motion: When a body executes to and fro motion about some fixed point, its motion is said to be oscillatory or vibratory.

Example: Mass attached to a spring, bob of pendulum, atoms in solid lattice etc.

3. Simple Harmonic Motion: A body executing simple harmonic motion oscillates in a straight line periodically in such a way that the acceleration is proportional to its displacement from a fixed point (called an equilibrium point), and the acceleration is always directed towards that point.

Note:

1. Body moves to and fro about a fixed point on a straight line.

2. Motion of the body will be periodic for all the points.

3. All harmonic motions are periodic but the reverse is not true.

4. Acceleration is maximum at end points and is zero at equilibrium position.

5. Acceleration is always directed towards the fixed point (equilibrium point) and is directly proportional to the displacement from it.