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Objective NCERT at your FINGERTIPS: Physics

NCERT

Chapter 14

Oscillations - all with Video Answers

Educators


Chapter Questions

01:57

Problem 1

Any position of sine antable coefficients. Which of the periods time penous Whaticians proved this result? following
(b) Carl Friedrich Gauss pythagoras
(a) Pythag (c) Leonhard Euler fean Baptiste Joseph Fourier
(d) Jean bapat

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01:46

Problem 2

Halley's comet appears after every The
(a) 72 years
(b) 74 years
(c) 76 years
(d) 78 years

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02:54

Problem 3

(c) Which one of the the earth about its axis.
(a) Rotation
(b) A freely suspended bar magnet displaced from and released. its $\mathrm{N}-\mathrm{S}$ direction of hands of a clock.
(c) Motion of hanus of from a bow.
(d) An arrow

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02:46

Problem 4

Which of the following $x$-t graphs does not represent periodic motion?

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01:12

Problem 5

If the frequency of human heart is $1.25 \mathrm{~Hz}$, the number of heart beats in 1 minute is
(a) 65
(b) 75
(c) 80
(d) 90

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03:58

Problem 6

In a certain oscillatory system, the amplitude of motion is $5 \mathrm{~m}$ and the time period is $4 \mathrm{~s}$. The time taken by the particle for passing between points which are at distances of $4 \mathrm{~m}$ and $2 \mathrm{~m}$ from the centre and on the same side of it will be
(a) $0.30 \mathrm{~s}$
(b) $0.32 \mathrm{~s}$
(c) $0.33 \mathrm{~s}$
(d) $0.35 \mathrm{~s}$

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02:46

Problem 7

A block of mass $m$ is attached to one end of a massless spring which is suspended vertically from a fixed point. The mass is held in hand so that the spring is neither stretched nor compressed. Suddenly the support of the hand is removed. The lowest position attained by the mass during oscillation is $4 \mathrm{~cm}$ below the point, where it was held in hand. The amplitude of the oscillation is
(a) $1 \mathrm{~cm}$
(b) $2 \mathrm{~cm}$
(c) $3 \mathrm{~cm}$
(d) $4 \mathrm{~cm}$

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03:58

Problem 8

Out of the following functions representing motion of a particle which represents SHM?
1. $x=\sin ^{3} \omega t$
2. $x=1+\omega t+\omega^{2} t^{2}$
3. $x=\cos \omega t+\cos 3 \omega t+\cos 5 \omega t$
4. $x=\sin \omega t+\cos \omega t$
(a) Only 1
(b) Only 1 and 3
(c) Only 1 and 4
(d) Only 4

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03:13

Problem 9

Which of the following is not a characteristics of simple harmonic motion?
(a) The motion is periodic.
(b) The motion is along a straight line about the mean position.
(c) The oscillations are responsible for the energy conversion.
(d) The acceleration of the particle is directed towards the extreme position.

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01:32

Problem 10

The equation of motion of a simple hamonik motion is
(a) $\frac{d^{2} x}{d t^{2}}=-c^{2} x$
(b) $\frac{d^{2} x}{d t^{2}}=-v^{2} t$
(c) $\frac{d^{2} x}{d t^{2}}=-c u x$
(d) $\frac{d^{2} x}{d t^{2}}=-\mathrm{cot}$

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02:03

Problem 11

Which of the following expressions represent simple harmoni motion?
(c) $x=B \sin (\omega t+\beta)$
(d) $x=$ Asincut cos'ot

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02:01

Problem 12

If a simple harmonic motion is represented by $\frac{d^{2} x}{d t^{2}}+c x=0$, its time period is
(a) $2 \pi \sqrt{c}$
(b) $2 \pi c$
(c) $\frac{2 \pi}{\sqrt{\alpha}}$
(d) $\frac{2 \pi}{\alpha}$

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01:33

Problem 13

The time period of simple harmonic motion depends
upon
(a) amplitude (b) encist
(c) phase constant
(d) $\mathrm{mass}$

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02:26

Problem 14

Which of the following motions is not simple harmonic?
(a) Vertical oscillations of a spring
(b) Motion of a simple pendulum
(c) Motion of planet around the sun
(d) Oscillation of tiquid in a U-tube

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02:08

Problem 15

If $x, v$ and a represent the displacement, the velocity and the acceleration of a particle executing simple harmonic motion of time period $T$ then which of the following does not change?
(a) $\frac{a T}{v}$
(b) $a T+2 \pi v$
(c) $\frac{a T}{x}$
(d) $a^{2} T^{2}+4 \pi^{2} v^{2}$

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02:16

Problem 16

The function sincot - costat represents
(a) a simple harmonic motion with a period $\frac{\pi}{\omega}$.
(b) a simple harmonic motion with a period $\frac{2 \pi}{\omega}$.
(c) a periodic, but not simple harmonic motion with a period $\frac{\pi}{\omega}$,
(d) a periodic, but not simple harmonic motion with a period $\frac{2 \pi}{\omega}$.

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01:50

Problem 17

A particle executing simple harmonic motion with an amplitude $A$. The distance travelled by the particle in one time period is
(a) zero
(b) $A$
(c) $2 A$
(d) $4 A$

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02:14

Problem 18

Displacement vs time curve for a particle sin shown in the figure.
which of the following statements is correc??
(a) Phase of the oscillator is same at $t=0 \mathrm{~s}$ and

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02:47

Problem 19

Two simple harmonic motions are represented the equations. $y_{1}=10 \sin \frac{\pi}{4}(12 t+1), y_{2}=5\left(\sin 3 \mathrm{p} t+\sqrt{3} \cos \frac{3}{\mathrm{p}}\right)$
The ratio of their amplitudes is
(a) $1: 1$
(b) $1: 2$
(c) $3: 2$
(d) $2: 3$

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02:16

Problem 20

Figure shows the displacement-time graphs of the simple harmonic motions I and II. From the graph it follows that
(a) curve I has same frequency as that of curvell.
(b) curve I has frequency twice that of curve ll.
(c) curve I has frequency half that of curve II.
(d) curve I has frequency four times that of curvell.

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03:06

Problem 21

A vibratory motion is represented by
$$
\begin{aligned}
x=2 A \cos () t+A \cos \left(\omega t+\frac{\pi}{2}\right)+& A \cos (\omega t+\pi) \\
&+\frac{A}{2} \cos \left(\omega t+\frac{3 \pi}{2}\right) .
\end{aligned}
$$
The resultant amplitude of the motion is
(a) $\frac{9 \mathrm{~A}}{2}$
(b) $\frac{\sqrt{5} A}{2}$
(c) $\frac{5 A}{2}$
(d) $2 \mathrm{~A}$

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04:01

Problem 22

A particle executing SHM is described by the displacement function $x(t)=A \cos (\omega t+\phi)$ If the initial $(t=0)$ position of the particle is $I \mathrm{~cm}$, its initial velocity is $\pi \mathrm{cm} \mathrm{s}^{-1}$ and its angular frequency is $\pi \mathrm{s}^{-1}$, then the amplitude of its motion is
(a) $\pi \mathrm{cm}$
(b) $2 \mathrm{~cm}$
(c) $\sqrt{2} \mathrm{~cm}$
(d) $1 \mathrm{~cm}$

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02:01

Problem 23

Two particles execute simple harmonic motions of same amplitude and frequency along the same straight line. They cross one another when goingThe phase difference between Whectionts. displacements are one half of their osite ain their
of $\mathrm{f}^{0}$ when
(ci) $150^{\circ}$
is $\quad$ (c) $120^{\circ}$
the plitudes is (b) $30^{\circ}$ $60^{\circ}$ ne $\mathrm{SHM}$ of same amplitude and

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02:01

Problem 24

$60^{2}$ sute $\mathrm{SHM}$ of same amplitude and
(b) $\frac{2 \pi}{3}$
(a) $2 \mathrm{~kg}$ is attached to the spring $o$

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02:15

Problem 25

$2 \mathrm{~kg}$ is attached to the sprmz= block of mass $20 \mathrm{~N} \mathrm{~m}^{-1}$. The block is pulled to a spring constant son of $5 \mathrm{~cm}$ from its equilibrium position at distance of 2 , on a horizontal frictionless surface from rest at $x=0$ on The displacement of the block at any time t is $t=0$
(a) $x=0.05 \sin 5 t \mathrm{~m}$
(b) $x=0.05 \cos 5 t \mathrm{~m}$
$x=0.5 \sin 5 t \mathrm{~m}$
(d) $x=5 \sin 5 t \mathrm{~m}$
(c) $x^{2}=0$ is filled in a tube

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05:21

Problem 26

(c) $x=0.2$ liquid of density $\rho$ is filled in a tube viscous liquio cross section, as shown in the A non viscer area
If the liquid is slightly depressed in one of the with $A$ as oscillates with a frequency figure. the liquid column arms.

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01:45

Problem 27

The circular motion of a particle with constant speed
is
(a) periodic and simple harmonic.
(b) simple harmonic but not periodic.
(c) neither periodic nor simple harmonic.
(d) periodic but not simple harmonic.

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01:42

Problem 28

Simple harmonic motion is the projection of uniform circular motion on
(a) $x$-axis
(b) $y$-axis
(c) reference circle
(d) any diameter of reference circle

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01:44

Problem 29

Figure shows the circular motion of a particle. The radius of the circle, the period, sense of revolution and the initial position are indicated in the figure. The simple harmonic motion of the $x$-projection of the radius vector of the rotating particle $P$ is
(a) $x=2 \cos \left(2 \pi t+\frac{\pi}{4}\right)$
(b) $x=2 \sin \left(2 \pi t+\frac{\pi}{4}\right)$
(c) $x=2 \sin \left(2 \pi t-\frac{\pi}{4}\right)$
(d) $x=2 \cos \left(2 \pi t-\frac{\pi}{4}\right)$

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01:39

Problem 30

In an SHM, $x$ is the displacement and $a$ is the acceleration at time $t$. The plot of $a$ against $x$ for one complete oscillation will be
(a) a straight line
(b) a circle
(c) an ellipse
(d) a sinusoidal curve

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02:02

Problem 31

Which one of the following statements is true for the velocity $v$ and the acceleration $a$ of a particle executing simple harmonic motion?
(a) When $v$ is maximum, $a$ is zero.
(b) When $v$ is zero, $a$ is zero.
(c) When $v$ is maximum, $a$ is maximum.
(d) Value of $a$ is zero, whatever may be the value of $v$.

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01:44

Problem 32

Which of the following relationships between the acceleration $a$ and the displacement $x$ of a particle executing simple harmonic motion?
(a) $a=2 x^{2}$
(b) $a=-2 x^{2}$
(c) $a=2 x$
(d) $a=-2 x$

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01:34

Problem 33

A particle executing simple harmonic motion wion an amplitude $A$ and angular frequency $\omega$. The ratio of maximum acceleration to the maximum velocity of the particle is
(a) $\omega A$
(b) $\omega^{2} \mathrm{~A}$
(c) $\omega$
(d) $\frac{\omega^{2}}{A}$

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02:04

Problem 34

The displacement-time graph for a particle executing SHM is as shown in figure.
Which of the following statements is correct?
(a) The velocity of the particle is maximum at $t=\frac{3}{4} T$
(b) The velocity of the partide is maximum at $t=\frac{T}{2}$
(c) The acceleration of the particle is maximum at $t=\frac{T}{4}$
(d) The acceleration of the particle is maximum at $t=\frac{3}{4} T$

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01:59

Problem 35

Displacement versus time curve for a particle executing SHM is as shown in figure.
At what points the velocity of the particle is zero?
(a) $A, C, E$
(b) $B, D, F$
(c) $A, D, F$
(d) $C, E, F$

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03:11

Problem 36

A particle executing SHM with time period $T$ and amplitude $A$. The mean velocity of the particle averaged over quarter oscillation is
(a) $\frac{A}{4 T}$
(b) $\frac{2 A}{T}$
(c) $\frac{3 A}{T}$
(d) $\frac{4 A}{T}$

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03:40

Problem 37

A particle is in linear simple harmonic motion $A O=O B=5 \mathrm{~cm}$
between two points $A$ and $B C=8 \mathrm{~cm}$
$B, 10 \mathrm{~cm}$ apart (figure). Take the direction from $A$ to $B$ as the tve direction. Which of the following statements is correct?
(a) The sign of acceleration and force on the particle when it is at $A$ is negative.
(b) The sign of acceleration and force on the particle when it is at $B$ is positive.
(c) The sign of velocity, acceleration and force on the partide when it is $3 \mathrm{~cm}$ away from $A$ going towards $B$ are positive.

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02:23

Problem 38

A particle executing SHM. The phase 56
between velocity and displacement is
(a) 0
(b) $\frac{\pi}{2}$
(c) $\pi$
(d) 2

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02:39

Problem 39

A particle executing SHM. The phase difet between acceleration and displacement is
(a) 0
(b) $\frac{\pi}{2}$
(c) $\pi$
(d) $\frac{3}{2^{7}}$

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03:24

Problem 40

A block of mass $m$ is attached to a spring of constant $k$ is free to oscillate with angular of $\mathrm{spn}$ in a horizontal plane without friction or clachy, It is pulled to a distance $x_{0}$ and pushed toward centre with a velocity $v_{0}$ at time $t=0$. The anplitud of oscillations in terms of $\omega, x_{0}$ and $v_{0}$ is
(a) $\sqrt{\frac{v_{0}^{2}}{\omega^{2}}-x_{0}^{2}}$
(b) $\sqrt{\omega^{2} v_{0}^{2}+x_{0}^{2}}$
(c) $\sqrt{\frac{x_{0}^{2}}{\omega^{2}}+v_{0}^{2}}$
(d) $\sqrt{\frac{v_{0}^{2}}{\omega^{2}}+x_{0}^{2}}$

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01:47

Problem 41

The piston in the cylinder head of a locomotiz has a stroke of $6 \mathrm{~m}$. If the piston executing simple harmonic motion with an angular frequency of $200 \mathrm{rad} \mathrm{min}^{-1}$, its maximum speed is
(a) $5 \mathrm{~m} \mathrm{~s}^{-1}$
(b) $10 \mathrm{~m} \mathrm{~s}^{-1}$ (c) $15 \mathrm{~m} \mathrm{~s}^{-1}$
(d) $20 \mathrm{~m} \mathrm{~s}^{-1}$

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03:00

Problem 42

A particle executing SHM according to the equation $x=5 \cos \left(2 \pi t+\frac{\pi}{4}\right)$ in SI units. The displacemet and acceleration of the particle at $t=1.5 \mathrm{~s}$ is
(a) $-3.0 \mathrm{~m}, 100 \mathrm{~m} \mathrm{~s}^{-2}$
(b) $+2.54 \mathrm{~m}, 200 \mathrm{~m} 5^{2}$
(c) $-3.54 \mathrm{~m}, 140 \mathrm{~m} \mathrm{~s}^{-2}$
(d) $+3.55 \mathrm{~m}, 120 \mathrm{~m} \mathrm{~s}^{-2}$

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02:37

Problem 43

A mass oscillates along the $x$-axis according to the law, $x=x_{0} \cos \left(\omega t-\frac{\pi}{4}\right)$. If the acceleration of the particle is written as $a=A \cos (\omega t+\delta)$, then
(a) $A=x_{0} \omega^{2}, \delta=\frac{3 \pi}{4}$
(b) $A=x_{0}, \delta=-\frac{\pi}{4}$
(c) $A=x_{0} \omega^{2}, \delta=\frac{\pi}{4}$
(d) $A=x_{0} \omega^{2}, \delta=-\frac{\pi}{4}$

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03:32

Problem 44

The $x-t$ graph of a particle undergoing simple harmonic motion is as shown in the figure.
of the particle at $t=\frac{4}{3} \mathrm{~s}$ is acceleration The accer
(a) $\frac{\sqrt{3}}{32} \pi^{2} \mathrm{~cm} \mathrm{~s}^{-2}$
(d) $-\frac{\sqrt{3}}{32} \pi^{2} \mathrm{~cm} \mathrm{~s}^{-2}$
(c) $\frac{\pi^{2}}{32} \mathrm{~cm} \mathrm{~s}^{-2}$

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01:53

Problem 45

Displacement of a particle executing simple motion is given by
$x$ is in metres where $x$ is and maximum speed of the particle is

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02:06

Problem 46

(c) 5 executes SHM of period 12 s. After two A particle executes of oscillation, geconds, it passes. thevelocity is found to be $3.142 \mathrm{~cm} \mathrm{~s}^{-1}$. The amplitude
of oscillations is
(c) $24 \mathrm{~cm}$
(d) $12 \mathrm{~cm}$
(b) $3 \mathrm{~cm}$
(a) $6 \mathrm{~cm}$ (D) 2

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02:43

Problem 47

(2) executing simple harmonic motion with
A particle amplitude $5 \mathrm{~cm}$ and a time period $0.2 \mathrm{~s}$. The an and acceleration of the particle when the
velocity and acco
$\begin{array}{ll}\text { displacement is } 5 \mathrm{~cm} \text { is } \\ \text { (a) } 0.5 \pi \mathrm{m} \mathrm{s}^{-1}, 0 \mathrm{~m} \mathrm{~s}^{-2} & \text { (b) } 0.5 \mathrm{~m} \mathrm{~s}^{-1},-5 \pi^{2} \mathrm{~m} \mathrm{~s}^{-2}\end{array}$
(c) $0 \mathrm{~m} \mathrm{~s}^{-1},-5 \pi^{2} \mathrm{~m} \mathrm{~s}^{-2}$
(d) $0.5 \pi \mathrm{m} \mathrm{s}^{-1},-0.5 \pi^{2} \mathrm{~m} \mathrm{~s}^{-2}$

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02:50

Problem 48

of mass $3 \mathrm{~kg}$ is under tension of $400 \mathrm{~N}$. The length of the stretched string is $25 \mathrm{~cm}$. If the transverse jerk is stuck at one end of the string how longdoes the disturbance take to reach the other end?
(a) $0.047 \mathrm{~s}$
(b) $0.055 \mathrm{~s}$
(c) $0.034 \mathrm{~s}$
(d) $0.065 \mathrm{~s}$

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01:34

Problem 49

9. Natural length of the spring is $40 \mathrm{~cm}$ and its spring constant is $4000 \mathrm{~N} \mathrm{~m}^{-1}$. A mass of $20 \mathrm{~kg}$ is hung from it. The extension produced in the spring is (Given $\left.g=9.8 \mathrm{~m} \mathrm{~s}^{-2}\right)$
(a) $4.9 \mathrm{~cm}$
(b) $0.49 \mathrm{~cm}$
(c) $9.4 \mathrm{~cm}$
(d) $0.94 \mathrm{~cm}$

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01:51

Problem 50

In simple harmonic motion, at the extreme positions
(a) kinetic energy is minimum, potential energy is maximum.
(b) kinetic energy is maximum, potential energy is minimum.
(c) both kinetic and potential energies are maximum.
(d) both kinetic and potential energies are minimum.

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01:44

Problem 51

The total energy of a simple harmonic oscillator is Proportional to
(a) amplitude
(b) square of amplitude
(c) frequency
(d) velocity

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01:25

Problem 52

A particle of mass $m$ executing SHM with amplitude $A$ and angular frequency $\omega$. The average value of the kinetic energy and potential energy over a period is
(a) $0, \frac{1}{2} m u^{2} A^{2}$
(b) $\frac{1}{2} m u^{2} A^{2}$,
(c) $\frac{1}{2} m \omega^{2} A^{2}, \frac{1}{2} m \omega^{2} A^{2}$
(d) $\frac{1}{4} m \omega^{2} A^{2}, \frac{1}{4} m x^{2} A^{2}$

Ajay Singhal
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02:46

Problem 53

A simple harmonic oscillator has a period $T$ and energy $E$. The amplitude of the oscillator is doubled. Choose the correct answer.
(a) Period and energy get doubled.
(b) Period gets doubled while energy remains the same.
(c) Energy gets doubled while period remains the same.
(d) Period remains the same and energy becomes four times.

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02:04

Problem 54

A particle executing simple harmonic motion with time period $T$. The time period with which its kinetic energy oscillates is
(a) $\mathrm{T}$
(b) $2 \mathrm{~T}$
(c) $4 T$
(d) $\frac{T}{2}$

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01:48

Problem 55

A particle executing SHM with an amplitude $A$. The displacement of the particle when its potential energy is half of its total energy is
(a) $\frac{A}{\sqrt{2}}$
(b) $\frac{A}{2}$
(c) $\frac{\mathrm{A}}{4}$
(d) $\frac{A}{3}$

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01:40

Problem 56

A block of mass $m$ is hanging vertically by spring of spring constant $k$. If the mass is made to oscillate vertically, its total energy is
(a) maximum at the extreme position
(b) maximum at the mean position
(c) minimum at the mean position
(d) same at all positions

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02:19

Problem 57

Frequency of variation of kinetic energy of a simple harmonic motion of frequency $n$ is
(a) $2 n$
(b) $n$
(c) $\frac{n}{2}$
(d) $3 n$

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01:23

Problem 58

For a particle executing simple harmonic motion, the displacement $x$ is given by $x=A \cos \omega t$. Identify the graph, which represents the variation of potential energy (U) as a function of time t and displacement $x$.
(a) I, III
(b) II, III
(c) I, IV
(d) II,IV

Ajay Singhal
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01:13

Problem 59

When the displacement of a particle executing SHM is one-fourth of its amplitude, what fraction of the total energy is the kinetic energy?
(a) $\frac{16}{15}$
(b) $\frac{15}{16}$
(c) $\frac{3}{4}$
(d) $\frac{4}{3}$

Ajay Singhal
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03:01

Problem 60

A block whose mass is $1 \mathrm{~kg}$ is fastened to a spring. The spring has a spring constant of $100 \mathrm{~N} \mathrm{~m}^{-1}$. The block is pulled to a distance $x=10 \mathrm{~cm}$ from its equilibrium position at $x=0$ on a frictionless surface from rest at $t=0 .$ The kinetic energy and potential energy of the block when it is $5 \mathrm{~cm}$ away from the mean position is
(a) $0.0375 \mathrm{~J}, 0.125 \mathrm{~J}$
(b) $0.125 \mathrm{~J}, 0.375 \mathrm{~J}$
(c) $0.125 \mathrm{~J}, 0.125 \mathrm{~J}$
(d) $0.375 \mathrm{~J}, 0.375 \mathrm{~J}$

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03:51

Problem 61

A body of mass $m$ is situated in a potential field $U(x)=U_{0}(1-\cos \alpha x)$ where $U_{0}$ and $\alpha$ are constants. The time period of small oscillations is
(a) $2 \pi \sqrt{\frac{m}{U_{0} \alpha}}$
(b) $2 \pi \sqrt{\frac{m}{U_{0} \alpha^{2}}}$
(c) $2 \pi \sqrt{\frac{m}{2 U_{0} \alpha}}$
(d) $2 \pi \sqrt{\frac{2 m}{U_{0} \alpha^{2}}}$

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01:28

Problem 62

The frequency of oscillations of a mass $m$ suspended by a spring is $v_{1}$. If the length of the spring is cut to one-half, the same mass oscillates with frequency $v_{2} .$ The value $v_{2} / v_{1}$ is
(a) 2
(b) $\sqrt{2}$
(c) 4
(d) $\sqrt{3}$

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01:33

Problem 63

Time period of oscillation of a spring is $12 \mathrm{~s}$ on earth. What shall be the time period if it is taken to moon?
(a) $6 \mathrm{~s}$
(b) $12 \mathrm{~s}$
(c) $36 \mathrm{~s}$
(d) $72 \mathrm{~s}$

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01:36

Problem 64

A $5 \mathrm{~kg}$ collar is attached to a spring of spring constant $500 \mathrm{~N} \mathrm{~m}^{-1}$. It slides without friction over a horizontal rod. The collar is displaced from its equilibrium position by $10 \mathrm{~cm}$ and released. The time period of oscillation is

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01:27

Problem 65

In the question number 64 , 231
acceleration of the collar is oq, the (a) $5 \mathrm{~m} \mathrm{~s}^{-2}$
(c) $15 \mathrm{~m} \mathrm{~s}^{-2}$
(b) $10 \mathrm{~m} \mathrm{~s}^{-2}$
(d) $20 \mathrm{~m} \mathrm{~s}^{-2}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:42

Problem 66

A body of mass $20 \mathrm{~g}$ connected to a spring of constant $k$, executes simple harmonic mo of frequency of $(5 / \pi) \mathrm{Hz}$. The value of
(a) $4 \mathrm{~N} \mathrm{~m}^{-1}$ (b) $3 \mathrm{~N} \mathrm{~m}^{-1}$
(c) $2 \mathrm{~N}_{\mathrm{m}-1}$
Two blocks each of mass $m_{j}$ (d) $5 \mathrm{~N}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:41

Problem 67

Two blocks each of mass $m$ is connected spring of spring constant $k$ as shown in the fo
If the blocks are displaced slightly in directions and released, they will execute harmonic motion. The time period of
(a) $2 \pi \sqrt{\frac{m}{k}}$
(b) $2 \pi \sqrt{\frac{m}{2 k}}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:11

Problem 68

An air chamber of volume $V$ has a neck of crost sectional area $a$ into which a light ball of $\mathrm{mass}$ just fits and can move up and down without friction The diameter of the ball is equal to that of the ned of the chamber. The ball is pressed down a little and released. If the bulk modulus of air is $B$, the time period of the oscillation of the ball is
(a) $T=2 \pi \sqrt{\frac{B a^{2}}{m V}}$
(b) $T=2 \pi \sqrt{\frac{B V}{m a^{2}}}$
(c) $T=2 \pi \sqrt{\frac{m B}{V a^{2}}}$
(d) $T=2 \pi \sqrt{\frac{m V}{B a^{2}}}$

Ajay Singhal
Ajay Singhal
Numerade Educator
02:42

Problem 69

A spring balance has a scale that reads from 0 to $50 \mathrm{~kg}$. The length of the scale is $20 \mathrm{~cm}$. A block of mass $m$ is suspended from this balance, when displaced and released, it oscillates with a period $0.5 \mathrm{~s}$. The value of $m$ is (Take $g=10 \mathrm{~m} \mathrm{~s}^{-2}$ )
(a) $8 \mathrm{~kg}$
(b) $12 \mathrm{~kg}$
(c) $16 \mathrm{~kg}$
(d) $20 \mathrm{~kg}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:12

Problem 70

A trolley of mass $3 \mathrm{~kg}$, as shown in figure, is connected to two identical springs, each of spring constant $600 \mathrm{~N} \mathrm{~m}^{-1}$. If the trolley is displaced from its equilibrium position by $5 \mathrm{~cm}$ and released, the maximum speed of the trolley is
(a) $0.5 \mathrm{~m} \mathrm{~s}^{-1}$
(b) $1 \mathrm{~m} \mathrm{~s}^{-1}$
(c) $2 \mathrm{~m} \mathrm{~s}^{-1}$
(d) $3 \mathrm{~m} \mathrm{~s}^{-1}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:56

Problem 71

A tray on two racmed on of spring shown in figure. springs. constant $k$, as tray is depressed a When the tray ised, it executes and released, motion of period $1.5 \mathrm{~s}$. When a little simple harmon $m$ is placed on the tray, the period of block os cillation becomes $3 \mathrm{~s}$. The value of $m$ is
(b) $20 \mathrm{~kg}$
$\begin{array}{ll}10 \mathrm{~kg} & \text { (d) } 40 \mathrm{~kg}\end{array}$
(a) $30 \mathrm{~kg}$
(c) $30 \mathrm{AB}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:30

Problem 72

Two identical springs of spring constant $k$ are
To block of mass $m$ and to fixed supports attached to a block in the figure. The time period of oscillation as hown
is
$\pi$
(a) $2 \pi \sqrt{\frac{m}{k}}$
(b) $2 \pi \sqrt{\frac{m}{2 k}}$
(c) $2 \pi \sqrt{\frac{2 m}{k}}$
(d) $\pi \sqrt{\frac{m}{2 k}}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:48

Problem 73

Match the Column I with Column II. Column II
(a) $A-p, B-q, C-s, D-r$
(b) $A-s, B-r, C-p, D-q$
(c) $\mathrm{A}-\mathrm{r}, \mathrm{B}-\mathrm{p}, \mathrm{C}-\mathrm{s}, \mathrm{D}-\mathrm{q}$
(d) $A-p, B-r, C-q, D-s$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:01

Problem 74

The time period of mass M when displaced from Inextensible its equilibrium position string and then released for the system as shown in figure is
(a) $2 \pi \sqrt{\frac{M}{k}}$
(b) $2 \pi \sqrt{\frac{M}{2 k}}$
(c) $2 \pi \sqrt{\frac{M}{4 k}}$
(d) $2 \pi \sqrt{\frac{2 M}{k}}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:23

Problem 75

To show that a simple pendulum executing a simple harmonic motion it is necessary to assume that
(a) length of the pendulum is small.
(b) mass of the pendulum is small.
(c) acceleration due to gravity is small.
(d) amplitude of the oscillation is small.

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:40

Problem 76

Motion of an oscillating liquid in a $U$ tube is
(a) periodic but not simple harmonic.
(b) non-periodic.
(c) simple harmonic and time period is independent of the density of the liquid.
(d) simple harmonic and time period is directly proportional to the density of the liquid.

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:36

Problem 77

What is the effect on the time period of a simple pendulum if the mass of the bob is doubled?
(a) Halved
(b) Doubled
(c) Becomes 8 times
(d) No effect

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:43

Problem 78

The acceleration due to gravity on the surface of the moon is $1.7 \mathrm{~m} \mathrm{~s}^{-2}$. The time period of a simple pendulum on the moon if its time period on the earth is $3.5 \mathrm{~s}$ is (Given, $g=9.8 \mathrm{~m} \mathrm{~s}^{-2}$ ).
(a) $2.2 \mathrm{~s}$
(b) $4.4 \mathrm{~s}$
(c) $8.4 \mathrm{~s}$
(d) $16.8 \mathrm{~s}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:13

Problem 79

Consider a pair of identical pendulums, which oscillate with equal amplitude independently such that when one pendulum is at its extreme position making an angle of $2^{\circ}$ to the right with the vertical, the other pendulum makes an angle of $1^{\circ}$ to the left of the vertical. The phase difference between the pendulums is
(a) $\frac{\pi}{2}$
(b) $\frac{2}{3} \pi$
(c) $\frac{3}{2} \pi$
(d) $\pi$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:32

Problem 80

Two pendulums differ in lengths by $22 \mathrm{~cm}$. They oscillate at the same place so that one of them makes 30 oscillations and the other makes 36 oscillations during the same time. The lengths (in $\mathrm{cm}$ ) of the
pendulums are
$$
\begin{array}{ll}\text { (b) } 60 \text { and } 38\end{array}
$$
(a) 72 and 50
(c) 50 and 28
(d) 80 and 58

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:54

Problem 81

The time period of a simple pendulum on the surface of the earth is $4 \mathrm{~s}$. Its time period on the surface of the moon is
(a) $4 \mathrm{~s}$
(b) $s s$
(c) $10 \mathrm{~s}$
(d) $12 \mathrm{~s}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:00

Problem 82

A disc of radius $R=10 \mathrm{~cm}$ oscillates as a physical pendulum about an axis perpendicular to the plane of the disc at a distance $r$ from its centre. If $r=\frac{R}{4}$, the approximate period of oscillation is (Take $\left.g=10 \mathrm{~m} \mathrm{~s}^{-2}\right)$
(a) $0.84 \mathrm{~s}$
(b) $0.94 \mathrm{~s}$
(c) $1.26 \mathrm{~s}$
(d) $1.42 \mathrm{~s}$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:56

Problem 83

A simple pendulum suspended from the roof of a lift oscillates with frequency $v$ when the lift is at rest. If the lift talls freely under gravity, its frequency of oscillation becomes
(a) zero
(b) $v$
(c) 20
(d) infinite

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:35

Problem 84

A simple pendulum of length $L$ and having a bob of mass $m$ is suspended in a car. The car is moving on a circular track of radius $R$ with a uniform speed $v$. If the pendulum makes small oscillations in a radial direction about its equilibrium position, its time period of oscillation is
(a) $T=2 \pi \sqrt{\frac{L}{g}}$
(b) $T=2 \pi \sqrt{\frac{L}{\sqrt{g^{2}+\frac{v^{4}}{R^{2}}}}}$
(c) $T=2 \pi \sqrt{\frac{L}{\sqrt{g^{2}+\frac{v^{2}}{R}}}}$
(d) $T=2 \pi \sqrt{\frac{L}{g^{2}-\frac{v^{4}}{R^{2}}}}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:23

Problem 85

A simple pendulum executing SHM with a period of $6 \mathrm{~s}$ between two extreme positions $B$ and $C$ about a point $O$. If the length of the arc $B C$ is $10 \mathrm{~cm}$, how long will the pendulum take the move from position $C$ to a position $D$ towards $O$ exactly midway between $C$ and $O ?$
(a) $0.5 \mathrm{~s}$
(b) $1 \mathrm{~s}$
(c) $1.5 \mathrm{~s}$
(d) $3 \mathrm{~s}$

Ajay Singhal
Ajay Singhal
Numerade Educator
02:19

Problem 86

The length of a seconds pendulum on the surface of earth is $1 \mathrm{~m}$. Its length on the surface of the moon is
(a) $\frac{1}{6} \mathrm{~m}$
(b) $1 \mathrm{~m}$
(c) $\frac{1}{36}$ r
(d) $36 \mathrm{~m}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:21

Problem 87

The length of the simple pendulum which ticks seconds is
(a) $0.5 \mathrm{~m}$
(b) $1 \mathrm{~m}$
(c) $1.5 \mathrm{~m}$
(d) $2 \mathrm{~m}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
03:33

Problem 88

A rectangular block of mass $m$ and area of crosssection $A$ floats in a liquid of density $\rho$. If it is given a small vertical displacement from equilibrium it undergoes oscillation with a time period $T$. Then
(a) $T \propto \frac{1}{\sqrt{m}}$
(b) $T_{\infty} \sqrt{p}$
(c) $T \propto \frac{1}{\sqrt{A}}$
(d) $T \propto \frac{1}{\rho}$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
02:27

Problem 89

A sphere of mass $m$ makes SHM in a hemispherical bowl $A B C$ and it moves from $A$ to $C$ and back to $A$ via $A B C$, so that $P B=h$. If acceleration due to gravity is $g$ the speed of when it just crosses the point $B$ is
(a) $2 g h$
(b) $m g h$
(c) $\sqrt{2 \mathrm{gh}}$
(d) $g h$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:21

Problem 90

A particle oscillating under a force $\vec{F}=-k \vec{x}-b_{i}$ is $(k$ and $b$ are constants)
(a) simple harmonic oscillator
(b) linear oscillator
(c) damped oscillator
(d) forced oscillator

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:34

Problem 91

Which of the following displacement-time graphs represent damped harmonic oscillation?

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:22

Problem 92

Which of the following energy-time graphs represents damped harmonic oscillator?

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:59

Problem 93

of mass $200 \mathrm{~g}$ executing SHM under the
for its amplitude to drop to half of its initial value is $\ln (1 / 2)=-0.693)$
$\begin{array}{llll}\text { (Given, In (lil) } & \text { (b) } 9 \mathrm{~s} & \text { (c) } 4 \mathrm{~s} & \text { (d) } 11 \mathrm{~s}\end{array}$
(a) $7 \mathrm{~s}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
02:20

Problem 94

In the question number 93 , the time elapsed for its mechanical energy to drop half of its initial value is
(a) $2.5 \mathrm{~s}$
(b) $3.5 \mathrm{~s}$
(c) $4.5 \mathrm{~s}$
(d) $7.5 \mathrm{~s}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:05

Problem 95

In case of force oscillations of a body force is constant throughout.
(a) driving
(b) driving force is to be applied only momentarily.
(c) driving force has to be periodic and continuous.
(d) driving force is not required.

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:09

Problem 96

Resonance is an example of
(a) forced oscillation
(b) damped oscillation
(c) free oscillation
(d) none of these In case

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:33

Problem 97

In case of a forced oscillation, the resonance peak becomes very sharp when the
(a) restoring force is small.
(b) damping force is small.
(c) quality factor is small.
(d) applied periodic force is small.

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:25

Problem 98

At resonance, the amplitude of forced oscillations is
(a) minimum
(b) maximum
(c) zero
(d) none of these

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:59

Problem 99

Which of the following statements is correct?
(a) Every periodic motion is simple harmonic motion.
(b) In simple harmonic motion the period is proportional to the square of the amplitude of oscillation.
(c) In simple harmonic motion the phase constant depends on initial condition.
(d) The resonance frequency of a driven oscillator depends on the damping.

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:48

Problem 100

A block of mass $m$ is attached to a spring of spring constant $k$ and has a natural frequency $\omega_{0}$. An external force $F(t)$ proportional to cos wt $\left(\omega \neq \omega_{0}\right)$ is applied to the oscillator. The time displacement of the oscillator will be proportional to
(a) $\frac{m}{\omega_{0}^{2}-\omega^{2}}$
(b) $\frac{1}{m\left(\omega_{0}^{2}-\omega^{2}\right)}$
(c) $\frac{1}{m\left(\omega_{0}^{2}+\omega^{2}\right)}$
(d) $\frac{m}{\omega_{0}^{2}+\omega^{2}}$

Mahendra Kumar
Mahendra Kumar
Numerade Educator