Question

Out of the following functions representing motion of a particle which represents $$SHM$$  ?
$$\eqalign{ & {\text{I}}{\text{.}}\,y = \sin \,\omega t - \cos \,\omega t \cr & {\text{II}}{\text{.}}\,y = {\sin ^3}\,\omega t \cr & {\text{III}}{\text{.}}\,y = 5\cos \left( {\frac{{3\pi }}{4} - 3\omega t} \right) \cr & {\text{IV}}{\text{.}}\,y = 1 + \omega t + {\omega ^2}{t^2} \cr} $$

A. Only (IV) does not represent $$SHM$$
B. (I) and (III)  
C. (I) and (II)
D. Only (I)
Answer :   (I) and (III)
Solution :
For a simple harmonic motion,
$$a \propto \frac{{{d^2}y}}{{d{t^2}}} \propto - y$$
Hence, equations $$y = \sin \omega t - \cos \omega t$$    and $$y = 5\cos \left( {\frac{{3\pi }}{4} - 3\omega t} \right)$$    are satisfying this condition and equation $$y = 1 + \omega t + {\omega ^2}{t^2}$$    is not periodic and $$y = {\sin ^3}\omega t$$   is periodic but not simple hormonic motion.

Releted MCQ Question on
Oscillation and Mechanical Waves >> Simple Harmonic Motion (SHM)

Releted Question 1

Two bodies $$M$$ and $$N$$ of equal masses are suspended from two separate massless springs of spring constants $${k_1}$$ and $${k_2}$$ respectively. If the two bodies oscillate vertically such that their maximum velocities are equal, the ratio of the amplitude of vibration of $$M$$ to that of $$N$$ is

A. $$\frac{{{k_1}}}{{{k_2}}}$$
B. $$\sqrt {\frac{{{k_1}}}{{{k_2}}}} $$
C. $$\frac{{{k_2}}}{{{k_1}}}$$
D. $$\sqrt {\frac{{{k_2}}}{{{k_1}}}} $$
Releted Question 2

A particle free to move along the $$x$$-axis has potential energy given by $$U\left( x \right) = k\left[ {1 - \exp \left( { - {x^2}} \right)} \right]$$      for $$ - \infty \leqslant x \leqslant + \infty ,$$    where $$k$$ is a positive constant of appropriate dimensions. Then

A. at points away from the origin, the particle is in unstable equilibrium
B. for any finite nonzero value of $$x,$$ there is a force directed away from the origin
C. if its total mechanical energy is $$\frac{k}{2},$$  it has its minimum kinetic energy at the origin.
D. for small displacements from $$x = 0,$$  the motion is simple harmonic
Releted Question 3

The period of oscillation of a simple pendulum of length $$L$$ suspended from the roof of a vehicle which moves without friction down an inclined plane of inclination $$\alpha ,$$ is given by

A. $$2\pi \sqrt {\frac{L}{{g\cos \alpha }}} $$
B. $$2\pi \sqrt {\frac{L}{{g\sin \alpha }}} $$
C. $$2\pi \sqrt {\frac{L}{g}} $$
D. $$2\pi \sqrt {\frac{L}{{g\tan \alpha }}} $$
Releted Question 4

A particle executes simple harmonic motion between $$x = - A$$  and $$x = + A.$$  The time taken for it to go from 0 to $$\frac{A}{2}$$ is $${T_1}$$ and to go from $$\frac{A}{2}$$ to $$A$$ is $${T_2.}$$ Then

A. $${T_1} < {T_2}$$
B. $${T_1} > {T_2}$$
C. $${T_1} = {T_2}$$
D. $${T_1} = 2{T_2}$$

Practice More Releted MCQ Question on
Simple Harmonic Motion (SHM)


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