Standing Waves on a String - TAMU Physics & Astronomy



Standing Waves on a String

[pic]

Purpose:

1. Investigate the characteristics of standing waves by producing them on a string.

2. Determine how tension affects wave velocity in a string.

Equipment:

string vibrator, string, mass hanger, masses, meter stick, pulley, clamps

Procedure:

Your string vibrator will generate wave pulses at a constant frequency of 60 Hz. By adjusting the tension, a standing wave may be produced from the interference of the initial wave and its reflection from the other end. Careful manipulation of the string tension (and thus, wave speed) can yield various numbers of loops.

Remember, one loop equals one-half wavelength,

and velocity equals frequency times wavelength.

Complete the Data Table to find various numbers of loops by changing the tension in the string by changing the amount of hanging mass. The tension in the string is the weight (weight = mass x gravity) of the hanging mass. Keep a constant string length (1.5 - 2.5 m recommended) and fill in as much of the data table as you can find.

Conclusion:

1. Use the results contained in your data table to make a graph of “Wave Velocity vs Tension”. Write a sentence on your graph that states the mathematical relationship between the string’s wave velocity and the string’s tension.

2. Use the information from the data table and your graph to write a summary paragraph detailing the relationships found among tension, speed, number of loops, and wavelength while the frequency and string length are held constant. Do not forget to name sources of error in this activity.

Data Table

|# of loops (harmonic #) |Frequency, |string length, |hanging mass, |tension, |wave-length, |wave speed, |

| |Hz |m |kg |N |m |m/s |

|3 |60 | | | | | |

|4 |60 | | | | | |

|5 |60 | | | | | |

|6 |60 | | | | | |

|7 |60 | | | | | |

|8 |60 | | | | | |

|9 |60 | | | | | |

|10 |60 | | | | | |

|11 |60 | | | | | |

|12 |60 | | | | | |

|13 |60 | | | | | |

|14 |60 | | | | | |

Summary:

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download