measuring speed of waves in a solid.

Question 1

what does the incident pulse do to the wave and what is inversed?

Answer 1

shape of the wave doesn’t change as it passes along the string.
reflected wave is inverted.

Question 2

what happens with a constructive interference?

Answer 2

as 2 crests of waves pass though each other their amplitudes add together.
at a given set of frequencies this can produce a standing wave pattern.

Question 3

required practical: what are the learning outcomes?

Answer 3

1) make observations to calculate speed of waves along a stretched string using measurements of their frequency and wavelength.
2) discuss how the experiment could be improved.
3) describe how we could modify the experiment to determine the effect of changing the tension in the stretched string.

Question 4

required practical: what equipment do you need?

Answer 4

vibration generator.
suitable power supply (variable frequency.)
suitable string or elasticated cord.
set of 100g masses and hanger.
set of 10g masses and hanger.
wooden bridge.
pulley on a clamp.

Question 5

required practical: what are the instructions?

Answer 5

1) set up apparatus.
2) switch on vibration generator. (the string/cord should start to vibrate.)
3) clear wave pattern needs to be seen. (to do this adjust the tension in the string/ move wooden bridge to adjust length of string.
4) use a meter ruler to measure across many half wavelengths as possible (a half wave length is one loop.) then divide the total length by number of half waves, multiplying this number by 2 will give the wavelength.
5) frequency is the frequency of the power supply.
6) calculate the speed of the wave using thew equation: wave speed = frequency × wavelength.