This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Physics 1240 Homework 10 solutions Brief solutions to homework set #10. Your numbers will be different, but the idea is the same. I’m just using sample numbers here. 1. Decide whether each of the following statements are T-True, or F-False. (a) If an ideal string can vibrate in a pure standing wave with fundamental frequency f , then (with no changes in length, tension, or material) it can also be made to vibrate in a pure standing wave with frequency of f/ 2. False. The fundamental is the lowest frequency resonance, because it corresponds to the longest wavelength that “fits” on the string. A lower frequency wave wouldn’t fit. (See more explanation of this point in the answer to question 5, below.) (b) If you decrease the tension in a string, the frequency of its fundamental vibration will get higher. False. Lower tension means lower wave speed along the string (because v is proportional to √ Tension), which means lower frequency (because v = fλ and λ doesn’t change). (c) If you have a standing wave with frequency 5 times the fundamental, there are 5 internal nodes (not counting nodes at the end of the string). False. The 5th mode has 5 antinodes and 4 interior nodes. (d) If an ideal string can vibrate in a pure standing wave with frequency f , then (with no changes in length, tension, or material) it can also be made to vibrate in a pure standing wave with frequency of 3 f . True. The third harmonic has frequency f 3 = 3 f ....
View Full Document
This note was uploaded on 08/24/2010 for the course PHYS 1240 taught by Professor Holland,murray during the Spring '08 term at Colorado.
- Spring '08