Example 5
What is the frequency of a logitudinal wave if the period is 0.2s?
Answer
Use the equation f=1/t
f=1/0.2 = 5m/s
Example 6
If the distance from crest to crest is 16cm and the period is 0.2s, what is the speed of the oscillation in IB physics curriculum?
Answer
Use the equation v=fλ
v= 1/0.2 *0.16
v = 5*0.16 = 0.8m/s
Example 7
Explain why the magnitude of the tension in a string at the midpoint of an oscillation is greater than the weight of the pendulum bob.
Answer
The pendulum bob accelerates towards the centre of its circular path, so there is an upwards force. This adds to tension produced by weight.
Example 8
What is the shape of an amplitude frequency graph when the oscillation is lightly damped?
Answer
Similar to the graph below:
Example 9
What is meant by resonance with reference to the previous question?
Answer
In IB physics, resonance is when a particle is forced to oscillate at its natural frequency, it is the opposite to damping shown above as the amplitude usually greatly increases or is the maximum.
Example 10
How would the graph in question 8 change if the pendulum was immersed in water?
Answer
The immersion of water would cause the oscillation to be heavily damped. Therefore, there would be a lower amplitude everywhere on the graph; with a much broader resonance peak and the maximum moves to the left on the graph.
End of this topic!
Drafted by Gina