Standing waves

Physics LO

1. Standing waves

2. Definition: A standing wave can be described as the following equation: Where A(x) can be defined as

3. A(x) is a sine function, thus certain points on the function would have zero amplitude. Points where A(x)=0 are called nodes Points that move with the maximum possible amplitude are call antinodes

4. How to calculate location of nodes and antinodes Location of nodes: Location of antinodes

5. Question! Identify nodes and antinodes from the given graph:

6. ANSWER! Node: 0, 180, 360 Antinode: 90, 270

7. Standing waves on strings The equation:

8. The allowed frequencies are called harmonics or resonant frequencies and is represented by the equation:

9. Question! A violin string is 0.52m long and has a linear mass density of 3.58 x 10^(-4) kg/m. The tension in the string is kept at 100.0N. What is the wave speed in the string? By what amount should the tension be changed to decrease the fundamental frequency by 10 HZ?

10. ANSwer ! A) V= 589m/s B) (Hint: first find the original fundamental frequency and then calculate) Amount of tension needs to be changed: 3.5N

11. Thank you for watching!