Oscillation - NEET Physics Questions
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Oscillation

Question 1: moderate

A simple harmonic motion has an amplitude A and time period T. The time required by it to travel from x = A to x = A/2 is :

1. T/6
2. T/4
3. T/3
4. T/12
View Answer

To find the time required for a particle in Simple Harmonic Motion (SHM) to travel from \( x = A \) to \( x = \frac{A}{2} \), we can use the following steps:

1. Angular Frequency (\( \omega \)):
\[
\omega = \frac{2\pi}{T}
\]

2. Displacement in SHM:
The position \( x(t) \) in SHM can be described by:
\[
x(t) = A \cos(\omega t)
\]

3. Finding Time for Positions:
- For \( x = A \):
\[
A \cos(\omega t_1) = A;  \cos(\omega t_1) = 1 ; t_1 = 0
\]

- For \( x = \frac{A}{2} \):
\[
\frac{A}{2} = A \cos(\omega t_2 ; \cos(\omega t_2) = \frac{1}{2} ; \omega t_2 = \frac{\pi}{3}
\]
\[
t_2 = \frac{\pi}{3\omega} = \frac{\pi T}{6}
\]

4. Time Interval:
The time taken to travel from \( x = A \) to \( x = \frac{A}{2} \) is:
\[
\Delta t = t_2 - t_1 = \frac{\pi T}{6} - 0 = \frac{T}{6}
\]

Thus, the time required to travel from \( x = A \) to \( x = \frac{A}{2} \) is:
\[{\frac{T}{6}}
\]

Question 2: moderate

A particle is executing SHM with amplitude A and has maximum velocity V0. Its speed at displacement A/2 will be

1. (√3)V0/2
2. V0/√2
3. V0
4. V0/4
View Answer

In Simple Harmonic Motion (SHM), the relationship between displacement, velocity, and amplitude can be described using the following equations.

1. The maximum speed \( V_0 \) is given by:
\[
V_0 = \omega A
\]
where \( \omega \) is the angular frequency.

2. The speed \( v \) at a displacement \( x \) in SHM is given by the formula:
\[
v = \sqrt{V_0^2 - \left(\frac{\omega x}{\omega A}\right)^2}
\]
Simplifying this using \( \omega = \frac{V_0}{A} \):
\[
v = \sqrt{V_0^2 - \left(\frac{V_0}{A} \cdot x\right)^2}
\]
Substituting \( x = \frac{A}{2} \):
\[
v = \sqrt{V_0^2 - \left(\frac{V_0}{A} \cdot \frac{A}{2}\right)^2}
\]
\[
v = \sqrt{V_0^2 - \left(\frac{V_0}{2}\right)^2}
\]
\[
v = \sqrt{V_0^2 - \frac{V_0^2}{4}} = \sqrt{\frac{3V_0^2}{4}} = \frac{\sqrt{3}}{2} V_0
\]

Thus, the speed of the particle at displacement \( \frac{A}{2} \) is:
\[{\frac{\sqrt{3}}{2} V_0}
\]

Question 3: easy

If the maximum velocity and acceleration of a particle executing SHM are equal in magnitude, the time period will be

1. 1.57 sec.
2. 3.14 sec.
3. 6.28 sec.
4. 12.56 sec.
View Answer

In simple harmonic motion (SHM), the maximum velocity \( v_{\text{max}} \) and maximum acceleration \( a_{\text{max}} \) are given by:

\[
v_{\text{max}} = \omega A \quad \text{and} \quad a_{\text{max}} = \omega^2 A
\]

where:
- \( \omega \) is the angular frequency,
- \( A \) is the amplitude.

 Solution:

1. Given that \( v_{\text{max}} = a_{\text{max}} \), we have:
\[
\omega A = \omega^2 A
\]

2. Dividing both sides by \( A \) (assuming \( A \neq 0 \)):
\[
\omega = \omega^2
\]

3. Solving for \( \omega \):
\[
\omega = 1 \, \text{rad/s}
\]

4. Time Period \( T \):
\[
T = \frac{2\pi}{\omega} = \frac{2\pi}{1} = 2\pi \approx 6.28 \, \text{s}
\]

Answer:
The time period of the particle is **6.28 seconds**.

Question 4: moderate

The instantaneous displacement of a simple harmonic oscillator is given by :

y = Acos (ωt + π/4) .

Its speed will be maximum at the time

1. 2π/ω
2. ω/2π
3. ω/π
4. π/4ω
View Answer

For the SHM given by:

\[
y = A \cos(\omega t + \frac{\pi}{4})
\]

Solution:

1. Velocity: The velocity \( v \) is the derivative of \( y \) with respect to \( t \):
\[
v = \frac{dy}{dt} = -A \omega \sin(\omega t + \frac{\pi}{4})
\]

2. Maximum Speed: The speed will be maximum when \( \sin(\omega t + \frac{\pi}{4}) = \pm 1 \).

Therefore,
\[
\omega t + \frac{\pi}{4} = \frac{\pi}{2}
\]

3. Solving for \( t \):
\[
\omega t = \frac{\pi}{2} - \frac{\pi}{4} = \frac{\pi}{4}
\]

\[
t = \frac{\pi}{4\omega}
\]

Answer:
The speed will be maximum at \( t = \frac{\pi}{4\omega} \).

Question 5: moderate

A particle is executing SHM. Then, the graph of velocity as a function of displacement is a/an :

1. Straight line
2. Circle
3. Ellipse
4. Hyperbola
View Answer

In simple harmonic motion (SHM), the velocity \( v \) and displacement \( x \) of a particle are related by:

\[
v = \pm \sqrt{\omega^2 A^2 - \omega^2 x^2}
\]

where:
- \( \omega \) is the angular frequency,
- \( A \) is the amplitude.

 Solution:

1. Rearranging this equation, we get:
\[
\frac{v^2}{\omega^2 A^2} + \frac{x^2}{A^2} = 1
\]

2. This is the equation of an ellipse in the \( v \)-\( x \) plane.

Answer:
The graph of velocity as a function of displacement for a particle in SHM is an ellipse.

Question 6: easy

The equation of SHM of a particle is given as 2d²x/dt² + 32x = 0, where x is the displacement from the mean position. then time period of its oscillation (in seconds) is

1. 4
2. π/2
3. π/2√2
4.
View Answer

Given the SHM equation:

\[
2 \frac{d^2x}{dt^2} + 32x = 0
\]

We can rewrite it as:

\[
\frac{d^2x}{dt^2} + 16x = 0
\]

This equation is of the form:

\[
\frac{d^2x}{dt^2} + \omega^2 x = 0
\]

where \( \omega^2 = 16 \).

Solution:

1. Angular Frequency \( \omega \):
\[
\omega = \sqrt{16} = 4 \, \text{rad/s}
\]

2. Time Period \( T \):
\[
T = \frac{2\pi}{\omega} = \frac{2\pi}{4} = \frac{\pi}{2} \, \text{s}
\]

 Answer:
The time period of the oscillation is \( \frac{\pi}{2} \) seconds.

Question 7: easy

Two simple harmonic motions of angular frequency 10rad/sec and 100 rad s–¹ have the same displacement amplitude. The ratio of their maximum acceleration is

1. 1 : 10³
2. \[ 1:10^{4}\]
3. 1 : 10
4. 1 : 10²
View Answer

Solution:

1. Maximum Acceleration in SHM is given by:
\[
a_{\text{max}} = \omega^2 A
\]

2. Ratio of Maximum Accelerations:
\[
\frac{a_{\text{max}_2}}{a_{\text{max}_1}} = \frac{\omega_2^2 A}{\omega_1^2 A} = \frac{\omega_2^2}{\omega_1^2} = \frac{(100)^2}{(10)^2} = \frac{10000}{100} = 100
\]

Answer:
The ratio of their maximum accelerations is \( 1 : 100 \) or \( 1 : 10^2 \).

Question 8: easy

A particle executing SHM has amplitude 0.01 m and frequency 60 Hz. The maximum acceleration of the particle is

1. 60π² m/s²
2. 88π² m/s²
3. 150π² m/s²
4. 144π² m/s²
View Answer

Given:
- Amplitude, \( A = 0.01 \, \text{m} \)
- Frequency, \( f = 60 \, \text{Hz} \)

Solution:

1. Angular Frequency \( \omega \):
\[
\omega = 2 \pi f = 2 \pi \times 60 = 120 \pi \, \text{rad/s}
\]

2. Maximum Acceleration \( a_{\text{max}} \):
Maximum acceleration in SHM is given by:
\[
a_{\text{max}} = \omega^2 A
\]

Substitute values of \( \omega \) and \( A \):
\[
a_{\text{max}} = (120 \pi)^2 \times 0.01 = 14400 \pi^2 \times 0.01 = 144 \pi^2 \, \text{m/s}^2
\]

Answer:
The maximum acceleration of the particle is \( 144 \pi^2 \, \text{m/s}^2 \).

Question 9: moderate

The simple harmonic motion of a particle is represented by the equation, x = 4 cos [88t +π/4]. The frequency (in Hz) and the initial displacement (in m) of the particle are

1. 14 : 2√2
2. 16; 2√2
3. 14; 3√2
4. 16; 3√2
View Answer

Given the SHM equation:

\[
x = 4 \cos(88t + \frac{\pi}{4})
\]

Solution:

1. Frequency: The general form of SHM is \( x = A \cos(\omega t + \phi) \), where \( \omega = 2 \pi f \) (angular frequency).

Here, \( \omega = 88 \).

\[
f = \frac{\omega}{2 \pi} = \frac{88}{2 \pi} = 14 \, \text{Hz}
\]

2. Initial Displacement: The initial displacement \( x_0 \) is the value of \( x \) at \( t = 0 \).

Substitute \( t = 0 \) into the equation:
\[
x_0 = 4 \cos\left(\frac{\pi}{4}\right) = 4 \cdot \frac{\sqrt{2}}{2} = 2 \sqrt{2} \, \text{m}
\]

Answer:
The frequency is  14 Hz, and the initial displacement is \( 2 \sqrt{2} \, \text{m} \).

Question 10: easy

Average velocity of a particle performing SHM in one time period is:

1. Zero
2. Aω/2
3. Aω/2π
4. 2Aω/π
View Answer

As displacement in one time interval is zero. Average velocity is zero.