1. VIBRATIONS
NATURAL VIBRATIONS DAMPED VIBRATIONS FORCED VIBRATIONS

2. NATURAL VIBRATIONS : PERIODIC VIBRATIONS IN THE ABSENCE OF ANY EXTERNAL FORCE
REMEMBER: THESE VIBRATIONS CAN OCCUR ONLY IN VACUUM!!!!!!!
ONLY ONE FORCE IS ACTING: RESTORING FORCE

3. DAMPED VIBRATION: PERIODIC VIBRATIONS OF A BODY OF DECREASING AMPLITUDE IN THE PRESENCE OF A RESISTIVE FORCE
TWO FORCES ACT ON THE BODY – RESTORING FORCE AND FRICTIONAL FORCE

4. FORCED VIBRATION: VIBRATIONS OF A BODY TAKING PLACE DUE TO AN EXTERNAL PERIODIC FORCE
THREE FORCES ACT ON THE BODY – RESTORING FORCE, FRICTIONAL FORCE AND THE EXTERNAL PERIODIC FORCE

5. RESONANCE : WHEN THE FREQUENCY OF THE APPLIED FORCE IS EQUAL TO ITS NATURAL FREQUENCY, THE BODY VIBRATES WITH AN INCREASED AMPLITUDE