STANDARDPhysics-Oscillations

STANDARD Physics Simple Harmonic Motion MCQ Question

Type: MCQ-numerical-Medium-Class 11

Two simple harmonic motions are represented by the equations, y1=10sin(π4(12t+1))y_1 = 10\sin\left(\frac{\pi}{4}(12t + 1)\right), y2=5(sin3πt+3cos3πt)y_2 = 5(\sin 3\pi t + \sqrt{3}\cos 3\pi t). The ratio of their amplitudes is

A

1 : 1

B

1 : 2

C

3 : 2

D

2 : 3

Correct Answer

Option A

Detailed Explanation

To find the ratio of the amplitudes of the two simple harmonic motions, we first identify the amplitudes from their equations. For y1=10sin(π4(12t+1))y_1 = 10\sin\left(\frac{\pi}{4}(12t + 1)\right), the amplitude is 10. For y2=5(sin3πt+3cos3πt)y_2 = 5(\sin 3\pi t + \sqrt{3}\cos 3\pi t), we can rewrite it in the form Rsin(3πt+ϕ)R\sin(3\pi t + \phi), where R=52+(35)2=10R = \sqrt{5^2 + (\sqrt{3} \cdot 5)^2} = 10. Thus, both motions have an amplitude of 10, giving a ratio of 10:10 or 1:1. Other options are incorrect as they suggest different ratios that do not reflect the calculated amplitudes.

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