Damping (OCR A Level Physics)

A pendulum is oscillating in air and experiences damping. Which of the following statements is/are correct for the damping force acting on the pendulum?

1      It is always opposite in direction to acceleration. 2      It is always opposite in direction to velocity. 3      It is maximum when the displacement is zero. 

An object oscillates with simple harmonic motion. Which graph best shows the variation of its potential energy E with distance x from the equilibrium position?

A graph of amplitude against driving frequency is shown for a forced oscillator.

Which of the following statements are true after damping is increased?

1. The maximum amplitude for the oscillator will occur at a higher driving frequency

2. The peak on the graph will be flatter (less sharp)

3. The amplitude at twice the natural frequency of the oscillator will be reduced.

4. The natural frequency of the oscillator will be decreased

The velocity versus time graph for a damped oscillator is shown.

Which of the following graphs is correct, given the velocity versus time graph above?

A pendulum bob on the end of a string is displaced horizontally by a distance of 28 cm from the midline, which raises its height to 10 cm above the lowest point of the pendulum swing.  Assuming the system will oscillate with simple harmonic motion, what is the angular frequency of the pendulum bob when it is released?

An oscillator is forced to oscillate at different frequencies.

The graph of amplitude A against driving frequency f for this oscillator is shown.

The damping on the oscillator is now decreased.

Which of the following statements is/are correct?

1    The amplitude of the oscillations at any frequency decreases. 2    The maximum amplitude occurs at a lower frequency. 3    The peak on the graph becomes thinner.