4.1 - Harmonic motion - questions

0.5 - What is x ?

1 - What is the amplitude ?

2 - What is the period ?

3 - What is the frequency ?

4 - What is the angular frequency ?

5 - If you have x = 2cos(8t) . What is the amplitude, angular frequency, frequency and period ?

6 - What are the formulas for (1) displacement as a function of time (2) velocity as a function of time and (3) acceleration as a function of time ?

7 - What is the maximum displacement, velocity and acceleration ?

4.1 - Draw the curves of x, v and a as a function of time !

8 - What is the formula for velocity as a function of displacement ?

9 - What is the formula for acceleration as a function of displacement ?

9.5 - What are the formulas for (1) velocity and (2) acceleration for circular motion ?

4.2 - Harmonic motion and Energy - questions

10 - What are the formulas for (1) kinetic energy as a function of time and (2) kinetic energy as a function of displacement.

11 - What are the formulas for (1) total energy as a function of time and (2) total energy as a function of displacement.

12 - What are the formulas for (1) potential energy as a function of time and (2) potential energy as a function of displacement.

13 - Draw the curve of kinetic energy as a function of time.

14 - Draw the curve of potential energy as a function of time.

15 - Draw the curve of total energy as a function of time.

4.3 - Forced oscillations - questions

16 - What is damping ?

17 - Draw the curve of light damping.

18 - Draw the curve of medium strong damping.

19 - Draw the curve of critical damping.

20 - What is a) natural frequency, b) forced oscillations and c) resonance ?

21 - What is a resonance curve and what does it look like ?

22 - What does it mean that two oscillators are in phase ?

4.3 - Wave characteristics - questions

23 - What is the difference between a wave pulse and a continuous wave ?

24 - What does interference mean ?

25 - Draw a picture of a wave and describe what is amplitude, wavelength, wave speed and crest and through !

26 - How is the period of a wave defined ?

27 - How is the frequency of a wave defined and how can it be calculated from the period ?

28 - How can the wavelength for a wave be calculated from the period and the wave speed ?

29 - Draw and explain the difference between a displacement-time graph and a displacement-position graph.

30 - Give an example of a longitudinal wave.

4.4 - Wave properties - questions

31 - What are the laws of reflection ?

32 - What is the difference between reflection and refraction ?

33 - What is Snell's law, and draw a picture.

33.1 - What wave characteristics change when a wave goes from one medium to another ?

34 - What is diffraction ?

35 - What is normal light ?

36 - What is sound and how does a microphone work ?

37 - What is the speed of light ? What is the speed of sound ?





4.1 Harmonic oscillation






















Look at the data booklet:  









Look at the data booklet:  








4.2 Energy and harmonic motion

Look at the data booklet:  




Look at the data booklet:  


Note that total energy do not depend on time or displacement because it is constant and always the same whatever the time or displacement is.















4.3 Forced oscillations

Damping is when the oscillating system has to work against an external force from for example friction or air resistance.












Natural frequency: The frequency of the system when no external force is put on the system when it is oscillating.

Forced oscillation: When an external force is put on the system to force it to oscillate at a different frequency than the natural frequency

Resonance: an increase in amplitude when a system is forced to oscillate at its own natural frequency.








Oscillators that are in phase move together



4.4 Wave characteristics

The pulse is short while the wave is long:






Interference is when pulses are combined to give a smaller or larger pulse. When the pulse is larger one has constructive interference and when the pulse becomes smaller one talks about destructive interference.









The period (T) is the time it takes for one complete wave to pass a fix point. Unit: s.



The frequency (f) is the number of complete cycles that pass a fix point per second. Unit: Hz = 1/s.

f = 1/T


Look at the data booklet:

Velocity = distance / time

v = λ / T


The displacement-position graphs show the position of all the points in the wave at a particular time (it is a snapshot of the wave):



The displacement-time graphs show how the position of one point of the wave move with time:





Sound or the wave in a spring:



4.5 Wave properties


1. The incident angle = the reflected angle

2. the incident and reflected rays are in the same plane as the normal.



Reflection is when the wave hits a solid medium that the wave cannot continue in.

Refraction is the change of direction when a wave move from one medium to another.







When a wave goes from one medium to another the frequency (and period) will NOT change. Amplitude, wavelength and velocity will change.







Normal light from a lamp or the sun is called white light and it is a mixture of light with different wavelengths.

Each wavelength of light corresponds to a particular colour. The light that the eye can see varies from 400 nm (blue) to 800 nm (red). 1 nm = 10-9m.

The intensity of light (its amplitude) tells us who bright the light looks to an eye.

Light is a form of electromagnetic radiation and this radiation can have very different wavelengths corresponding to different types of waves:







The speed of light = 3•108 m/s (can be found in the data booklet)

The speed of sound = 330 m/s