- #1
fog37
- 1,568
- 108
Hello,
I am aware that there are specific oscillatory patterns than can form on on a string. These patterns are called normal modes and represent standing waves. Each standing wave has an associated frequency f which indicates the speed at which the string's points are moving up and down. Higher harmonics (modes) have higher frequency.
How do we solely excite a specific mode without exciting the other modes? For instance, can we excite the 3rd mode without exciting the fundamental or the other higher modes? Do we need to pull the string where the mode has one of its antinodes or make sure we force the string point where a node would not to displace? Usually, a higher harmonic has multiple nodes and multiple antinodes...
Clearly, we could excite a higher mode, the 4th one which has 4 antinodes, by pulling the string at rest where those points are on the string and keep the nodes from moving. We practically stretch the string so that is assume the shape of the mode. After that, the mode will continue its existence on its own and oscillate...
Thanks!
I am aware that there are specific oscillatory patterns than can form on on a string. These patterns are called normal modes and represent standing waves. Each standing wave has an associated frequency f which indicates the speed at which the string's points are moving up and down. Higher harmonics (modes) have higher frequency.
How do we solely excite a specific mode without exciting the other modes? For instance, can we excite the 3rd mode without exciting the fundamental or the other higher modes? Do we need to pull the string where the mode has one of its antinodes or make sure we force the string point where a node would not to displace? Usually, a higher harmonic has multiple nodes and multiple antinodes...
Clearly, we could excite a higher mode, the 4th one which has 4 antinodes, by pulling the string at rest where those points are on the string and keep the nodes from moving. We practically stretch the string so that is assume the shape of the mode. After that, the mode will continue its existence on its own and oscillate...
Thanks!