Question

A simple pendulum performs simple harmonic motion about $$x = 0$$  with an amplitude $$a$$ and time period $$T.$$ The speed of the pendulum at $$x = \frac{a}{2}$$  will be

A. $$\frac{{\pi a\sqrt 3 }}{{2T}}$$
B. $$\frac{{\pi a}}{T}$$
C. $$\frac{{3{\pi ^2}a}}{T}$$
D. $$\frac{{\pi a\sqrt 3 }}{T}$$  
Answer :   $$\frac{{\pi a\sqrt 3 }}{T}$$
Solution :
Use the equation of motion of a body executing $$SHM.$$
i.e. $$x = a\sin \omega t$$
As we know, the velocity of body executing $$SHM$$  is given by
$$\eqalign{ & v = \frac{{dx}}{{dt}} = a\omega \cos \,\omega t = a\omega \sqrt {1 - {{\sin }^2}\omega t} \cr & = \omega \sqrt {{a^2} - {x^2}} \cr & {\text{Here,}}\,x = \frac{a}{2} \cr & \therefore v = \omega \sqrt {{a^2} - \frac{{{a^2}}}{4}} = \omega \sqrt {\frac{{3{a^2}}}{4}} \cr & = \frac{{2T}}{T}\frac{{a\sqrt 3 }}{2} \cr & = \frac{{\pi a\sqrt 3 }}{T} \cr} $$

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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