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# Waves watch

1. The figure (attached) shows a sinusoidal wave travelling to the right along a rope. The dashed line represents the wave at t=0 and the solid line at t=25ms.

What is the speed, frequency and period of the wave?

So we know the amplitude is 0.2m and the wavelength is 2m, but not sure how to work out the rest..
Attached Images

2. How far does the wave move between 0 and 25 ms(between the black and dotted lines)? Do you know how to work out wave speed from this?
3. Use the diagram. Look at how far it is between one wavelength for the solid line, and look at how many squares the dashed line has passed after 25.

It looks like the wavelength is 2 metres, and the dashed line has passed 0.5 metres in 25 seconds. So the time period will be given by 25*4 = 100 seconds

Then Frequency is 1/Time Period = 1/100 Hz.

Speed = Frequency * Wavelength

Speed = 1/100 * 2 = 1/50 m/s
4. Another question for waves:
What is the relationship between phase difference andpath difference?

5. (Original post by A84)
Another question for waves:
What is the relationship between phase difference andpath difference?
Path difference is the difference in direction of travel when comparing two waves between each other or when referenced to their original direction. e.g. reflection, refraction etc.

Phase difference is the difference in timing (or expressed in degrees) between successive crests and troughs of two waves having the same period, when referenced to the same point in time.

http://www.bbc.co.uk/bitesize/higher...es/revision/1/
6. (Original post by uberteknik)
Path difference is the difference in direction of travel when comparing two waves between each other or when referenced to their original direction. e.g. reflection, refraction etc.

Phase difference is the difference in timing (or expressed in degrees) between successive crests and troughs of two waves having the same period, when referenced to the same point in time.

http://www.bbc.co.uk/bitesize/higher...es/revision/1/
True, but what about there relationship?
7. (Original post by A84)
True, but what about there relationship?
You need to think about where that reference point is and how far each wave travels to get to that reference point from their origin.

It will also depend on the speed of propagation of the waves travelling through different materials etc.

The relationship will completely depend on the specifics of each problem. Angles of incidence and reflection, refractive indexes, speed of propagation etc.
8. (Original post by uberteknik)
You need to think about where that reference point is and how far each wave travels to get to that reference point from their origin.

It will also depend on the speed of propagation of the waves travelling through different materials etc.

The relationship will completely depend on the specifics of each problem. Angles of incidence and reflection, refractive indexes, speed of propagation etc.
Thanks.

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