Physics

Oscillations and Periodic Motion

173 Questions

Oscillations and periodic motion describe the movement of objects repeating their paths in regular intervals. Key concepts include simple pendulums, kinetic energy variations, and mechanical resonance. This physics topic is vital for various competitive exams.

Simple pendulumTime period calculationsKinetic energy in SHMMechanical resonanceDamped oscillations

Oscillations and Periodic Motion Questions

Multiple choice

What is the amplitude of the oscillation?

  1. The maximum distance from the centre by which the pendulum moves.

  2. The time taken for one oscillation.

  3. It is the number of oscillations per second.

  4. The maximum distance from one end to another extreme the pendulum covers.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, the more the push, the more the distance the pendulum  will cover from its central position, the more its amplitude.

Multiple choice physics free, damped and forced oscillations damped harmonic motion damped oscillation free, forced and damped oscillations

The phenomenon in which the amplitude of oscillation of a pendulum decreases gradually is called

  1. decay period of oscillation

  2. damping

  3. building up of oscillation

  4. maintained oscillation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Whenever there is a damping force, it will slow down the motion of a pendulum, and ultimately it will make the pendulum stop. This phenomenon is called damping.

Multiple choice physics free, damped and forced oscillations damped harmonic motion damped oscillation free, forced and damped oscillations

The oscillations of a pendulum slow down due to :

  1. the force exerted by air and the force exerted by friction at the support

  2. the force exerted by air only

  3. the forces exerted by friction at the support

  4. they never slow down
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pendulum on its motion has friction particle. As a result of this frictional force slows down.

Multiple choice physics free, damped and forced oscillations damped harmonic motion damped oscillation free, forced and damped oscillations

In which of the following there is some loss of energy in the form of heat

  1. Forced vibrations

  2. Free vibration

  3. Damped vibrations

  4. All
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is our common experience that when a body is made to vibrate in a medium , the amplitude of the vibrating body continuously decreases with time and ultimately the body stops vibrating.this is called the damped vibrations.

Multiple choice force in shm oscillations oscillation and waves physics

An elastic ball of density $d$ is released and it falls through a height $h$ before striking the surface of liquid of density $\rho(d < \rho)$. The motion of ball is:

  1. Periodic

  2. S.H.M.

  3. Circular

  4. Parabolic
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When the ball hits the liquid, it experiences a buoyant force greater than its weight (since d < rho), causing it to decelerate and eventually rise. It will oscillate between the surface and the depth, making the motion periodic, but it is not SHM because the forces are not linear with displacement.

Multiple choice force in shm oscillations oscillation and waves physics

A body of mass 1/4 kg is in S.H.M and its displacement is given by the relation $y= 0.05 sin(20t+\dfrac{\pi }{2})$ m. If $t$ is in seconds, the maximum force acting on the particle is:

  1. $5$ N
  2. $2.5$ N
  3. $10$ N
  4. $0.25$ N
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$F= m\omega^{2}A$
$\omega = 20   rad / sec$
$A =   0.05   m$
Thus
$F= \dfrac{1}{4}\times 20\times 20\times \dfrac{1}{20}$
$=5 N $

Multiple choice resonance oscillations physics

Which of the following is an example of mechanical resonance?

  1. A child on a swing.

  2. A pendulum.

  3. A tuning fork.

  4. Nuclear magnetic resonance
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

$Answer:-$ A,B

Mechanical resonance is the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency or resonant frequency) than it does at other frequencies. It may cause violent swaying motions and even catastrophic failure in improperly constructed structures including bridges, buildings and airplanes—a phenomenon known as resonance disaster.

Various examples of mechanical resonance include:-

  • Most clocls keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.
  • The resonance of the basilar membranein the ear.
  • Making a child's swing swing higher by pushing it at each swing.
  • A wineglass breaking when someone sings a loud note at exactly the right pitch.

Multiple choice resonance oscillations physics

Destruction of buildings during an earthquake is an example of:

  1. mechanical resonance

  2. beats

  3. damped vibration

  4. critical vibration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During earthquake, when the frequency of earthquake becomes equal to the natural frequency of building, resonance (mechanical) occurs due to which amplitude of vibration of building increases and building get destroy.

Multiple choice resonance oscillations physics

Which of the following shows mechanical resonance?

  1. Balance wheel

  2. Pendulum

  3. Quartz crystal

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Answer:-$ D

Mechanical resonance is the tendency of a mechanicalsystem to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency or resonant frequency) than it does at other frequencies.
examples: Most clocks keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.

Multiple choice maths direct proportion and inverse proportion inverse proportion rule of three types of proportions

The length of a pendulum varies inversely as the square of the number of beats it makes per minute. If a pendulum, $65$ cm long, makes $27$ beats per minute, then the length of the pendulum that makes $24$ beats per minutes is 

  1. $91$ cm
  2. $85$ cm
  3. $81$ cm
  4. $71$ cm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Length $\alpha \cfrac{1}{(\text {No. of beats} )^2}$
$ \Rightarrow L = \cfrac{k}{\text {(beat)}^2}$, where $k$ is constant.
$\Rightarrow 65 = \cfrac{k}{(27)^2}$
$\Rightarrow k = 65 \times (27)^2$ 
Also, $k=L\times(24)^2$
$\Rightarrow 65 \times (27)^2= L \times(24)^2$
$\Rightarrow L = 81 cm $(approx)
Multiple choice physics types of energy law of conservation of energy the law of conservation of energy work, energy and machines

When a pendulum oscillates, it comes to rest after sometime because :

  1. energy lost by pendulum to overcome friction is gained by pendulum

  2. energy lost by pendulum to overcome its speed is gained by surrounding

  3. energy lost by pendulum to overcome friction is gained by surrounding

  4. energy lost by pendulum to overcome friction is gained by surrounding and pendulum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a pendulum oscillates, it comes to rest after sometime because energy lost by pendulum to overcome friction is gained by surrounding. Hence total energy of pendulum and surrounding system remains conserved.

Multiple choice physics free, damped and forced oscillations forced vibration forced vibrations free, forced and damped oscillations

A sphere of radius r is kept on a concave mirror of radius of curvature R. The arrangement is kept on a horizontal table (the surface of concave mirror is frictionless and sliding not rolling). If the sphere is displaced from its equilibrium position and left, then it executes S.H.M. The period of oscillation will be  

  1. $\pi \times { \left( \dfrac { (R-r)1.4 }{ g } \right) } $
  2. $2\pi \times { \left( \dfrac { R-r }{ g } \right) } $
  3. $\sqrt [ 2\pi ]{ \left( \dfrac { r\quad R }{ g } \right) } $
  4. ${ \left( \dfrac { R }{ g\quad r } \right) } $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For a sphere of radius r rolling/sliding in a concave mirror of radius R, the effective length of the pendulum is (R-r). The time period for a simple pendulum is T = 2*pi * sqrt(L/g). Substituting L = R-r, we get T = 2*pi * sqrt((R-r)/g).