# MHT-CET Physics Crash Course “Free and Forced Vibrations” Class 12

## “Free and Forced Vibrations” MHT-CET Class 12 Physics Crash Course | Chapter – Superposition of Waves

In this session G.S. Khairnar discussed the theory and MCQ’s of “Free and Forced Vibrations”. The session will be useful for all the aspirants of MHT-CET 2022. The session will be in Marathi and English.

### Free and Forced Vibrations:-

Hello dear students in previous articles we have learnt about the superposition of waves. Due to superposition of waves, when two waves are overlapped in opposite phase, the loops are produced which forms the phenomena of stationary waves. In this article we are going to discuss about the types of vibrations that involves in the study of waves, viz; free vibrations and forced vibrations.

Free Vibrations:-

The body is set up into vibrate with its own natural frequency called as free vibrations.

In free vibrations the energy of vibrating object continuously goes on decreasing due to presence of frictional forces like air resistance. Amplitude of vibration of body goes on decreasing continuously and comes to rest after some time.

• Characteristics:-
1. Frequency depends upon nature of body.
2. Energy of oscillating body goes decreasing.
3. The amplitude of oscillations goes on decreasing due to presence of air and frictional forces.
4. The force does not continuously acts on body.

e.g. oscillations of simple pendulum, vibrations of tuning fork.

Forced vibrations:-

The body is set in to vibrations due to external periodic forces called as forced vibrations.

A vibrating object sets nearby object in vibrations. Energy of first object is absorbed by the nearby object and it starts vibrating of their frequencies matches. The second object is said to be in forced vibrations.

• Characteristics:-
1. Frequency depends upon external frequency.
2. Energy of oscillating body remains constant.
3. The amplitude of oscillations remains constant.
4. The force continuously acts on body.

e.g. motion of drilling machine, working of stethoscope, resonance effect in earthquake are some examples of forced vibrations.

If any particle is performing oscillations with constant amplitude throughout, then the oscillations are known as undamped oscillations. When the motion of an oscillator is reduced by an external force, the oscillator and its motion are said to be damped.

### ♦जिल्हा नुसार जाहिराती ♦

अहमदनगर अकोला अमरावती औरंगाबाद भंडारा बुलढाणा
चंद्रपुर धुले गढ़चिरौली गोंदिया हिंगोली जलगांव
जालना कोल्हापुर लातूर मुंबई नागपुर नांदेड़
नंदुरबार नाशिक उस्मानाबाद पालघर परभानी पुणे
रायगढ़ रत्नागिरि सांगली सातारा सिंधुदुर्ग सोलापुर
ठाणे वर्धा वाशिम यवतमाल बीड

### ♦शिक्षणानुसार जाहिराती ♦

७ वी (7th) दहावी (SSC) बारावी (HSC) डिप्लोमा आय.टी.आय पदवी
पदव्युत्तर शिक्षण बी.एड एम.एड एल.एल.बी / एल.एल.एम बीएससी एमबीए
बीसीए एमसीए बी.कॉम एम.कॉम GNM/ANM एमएससी
बी.फार्म एम.फार्म बी.ई एम.ई BAMS/BHMS एम.बी.बी.एस / एम.डी
बी.टेक एम.टेक MS-CIT