Damped and Forced Harmonic Motion

IMPORTANT

Damped and Forced Harmonic Motion: Overview

This topic covers concepts, such as, Damped Oscillations, Damping Constant, Forced Oscillations, Amplitude Resonance in Forced Oscillations, Natural Frequency of a System, Driving Frequency & Free Oscillations etc.

Important Questions on Damped and Forced Harmonic Motion

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In a free oscillation,what happens to the amplitude,frequency and energy of the oscillating body?

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In case of a forced oscillation, the resonance peak becomes very sharp when the

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The vibrations that can continue even after the external force is removed are called free vibrations or natural vibrations.

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Natural frequency of a body depends on the shape, size, and _____ (elasticity/intensity) of the body.

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Explain why simple motion of pendulum stop after some time?

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Define damped harmonic motion.

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Which of the following differential equations represents a damped harmonic oscillator?

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When a damped harmonic oscillator completes 100 oscillations, its amplitude is reduced to 13rd  of its initial value. What will be its amplitude when it completes 200 oscillations?
 

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Compare the effect of damping on the resonance vibration of sonometer and of the air column.

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A damped oscillator consists of a spring-mass system with mass 2 kg and spring of spring constant 10 N m-1. The damping force is given by F=-bdxdt where b=280 g s-1. The time required for the amplitude of the oscillations to reduce to one-fourth 14th of its initial value is: (Assume ln2=0.7)

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In the following a statement of Assertion is followed by a statement of Reason.

Assertion: In damped oscillations, the oscillator experiences both conservative and non-conservative forces.

Reason: In damped oscillations mechanical energy of oscillator decreases with time.

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When a body of natural frequency n is subjected to the external force vibrating with frequency p, the body vibrates with frequency p under steady state with an amplitude which depends upon

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In an experiment to find the loss of energy with respect to time in the case of a swinging simple pendulum, the graph between the square of amplitude and time is best represented by

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A metal wire of linear mass density of 9.8 g m-1is stretched with a tension of kg-wt between two rigid supports 1 m apart. The wire passes at its middle point between the poles of a permanent magnet and it vibrates in resonance when carrying an alternating current of frequency n. the frequency n of the alternating sources is

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A particle, with restoring force proportional to displacement and resisting force proportional to velocity is subjected to a force.

F=F0sinωt

If the amplitude of the particle is maximum for ω=ω1 and the energy of the particle is maximum for ω=ω2 then

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The amplitude of damped oscillator becomes 13rd of the original in 2 s. Its amplitude after 6 s is 1n times the original. Then, n is equal to,

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If the differential equation given by

d2ydt2+2kdydt+ω2y=F0 sin pt

Describes the oscillatory motion of body in a dissipative medium under the influence of a periodic force, then the state of maximum amplitude of the oscillation is a phenomena of

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The amplitude of a damped oscillator becomes 13rd in 2 s. If its amplitude after 6 s is 1n times the original amplitude, the value of n is

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The angular frequency of the damped oscillator is given by, ω = k m - r 2 4 m 2  where k is the spring constant, m is the mass of the oscillator and r is the damping constant. If the ratio r 2 mk  is 8%, the change in time period compared to the undamped oscillator is approximately as follows :

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A simple pendulum after some time becomes slow in motion and finally stops due to