Question

Vibrations, whose amplitude of oscillations decrease with time is called
(A) Free vibrations
(B) Forced vibrations
(C) Damped vibrations
(D) None of these

Answer 1

Hint: We will first start with understanding the quantities given in the question. Starting with vibrations which are defined as the to and fro movement of an object from its mean position. In other words, the vibrations occur when an object performs oscillations about an equilibrium point.

Complete step by step solution:
We have discussed the free vibrations and now we will discuss the quantities given in the options and their properties.
Free vibration occurs when there are no external forces that mean if external forces are absent then the system oscillates due to the action of forces that exist within the system itself. When the system reaches the limit of stability then the amplitude of the free vibrations is found to be constant that means the amplitude will neither grow nor decay.
Forced vibrations occur when the system is continuously driven by an external force. It can be considered as a time-varying disturbance in the system. In the case of forced vibrations, the amplitude of the vibrations always remains constant by the application of some external force.
Damped vibrations occur when the energy of the system reduces over time that means the amplitude of the oscillations decreases with time and hence the system is considered as damped.
Hence the option (C) is the correct answer.

Note:
Vibration is considered as one of the most interesting phenomena that are observed in the universe. It is one of the most important subjects that have very large engineering applications. It is found that every object in the universe vibrates.