Soldiers are asked to break step while marching across a bridge in order to avoid
- A.Damping
- B.Resonance
- C.Interference
- D.Refraction
Correct answer
Explanation
The correct answer is B, resonance. If the frequency of the soldiers' rhythmic steps happens to match the natural frequency of the bridge, the bridge is driven at its own frequency and its amplitude of vibration can build up to a dangerous level; breaking step destroys the rhythm and avoids the risk. Option A is wrong because damping is the gradual loss of energy that makes oscillations die away, which is a protection and not a danger. Option C is wrong because interference is the combination of two waves to give regions of large and small disturbance, a wave phenomenon unrelated to the marching of troops. Option D is wrong because refraction is the bending of a wave as it passes from one medium to another. Resonance also explains radio tuning, the shattering of a glass by a loud note and the sound box of a musical instrument.
Read the full article: Oscillations: Simple Harmonic Motion and Pendulum Notes
Practice Questions
View allIf a particle is moving with simple harmonic motion, the velocity is _________ at the mean position.
- A.Maximum
- B.Zero
- C.Minimum
- D.None of these
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In simple harmonic motion the velocity is given by omega times the square root of A squared minus x squared.
Read the full explanation →A child is sitting on a swing. Its minimum and maximum heights from the ground are 0.75 m and 2 m respectively. Its maximum speed will be
- A.10 m/s
- B.5 m/s
- C.8 m/s
- D.15 m/s
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A swing is a pendulum, and its speed is greatest at the lowest point, where all the potential energy gained at the top has turned into kinetic energy.
Read the full explanation →The time period of a simple pendulum does not depend on which of the following?
- A.The length of the pendulum
- B.The mass of the bob
- C.The acceleration due to gravity
- D.All of these
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The time period of a simple pendulum is two pi times the square root of the length divided by g, in which the mass of the bob does not appear at all; a heavy bob and a light bob of the same length keep the same time, which is the…
Read the full explanation →The length of a second's pendulum, at a place where the acceleration due to gravity is 9.8 m/s squared, is nearly
- A.1 metre
- B.2 metres
- C.0.5 metre
- D.9.8 metres
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A second's pendulum is one whose time period is exactly two seconds, so that each swing from one side to the other takes one second.
Read the full explanation →If the length of a simple pendulum is made four times its original value, its time period will become
- A.Four times
- B.Two times
- C.Half
- D.One fourth
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The time period varies as the square root of the length, so multiplying the length by four multiplies the period by the square root of four, that is by two; to double the period of a pendulum its length must be made four times.
Read the full explanation →