# Sound waves and vibrations

[SOLVED] Sound waves and vibrations

I read a post here on PF dated back in Nov 2003.
'Security' needed some help with his Physics exam... and what a coincidence! I'm also working on that same exam now.

PF Admin 'chroot' helped him with the questions...
and I got confused with some of his answers. So I want to make sure now if I'm really wrong and he's right.

I also sent a private msg to Security but he hasn't responded.

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Warren's (chroot) answer was TRUE for the statement:
--A pendulum with a mass of 10g and a length of 20 cm swings back and forth MORE frequently than a pendulum with a mass of 20g and a length of 10cm.

MY ANSWER... is FALSE because my textbook (which was also Security's) clearly says that "A long pendulum has a longer period that a shorter pendulum; that is, it swings back and forth more slowly--less frequently--than a short pendulum."
This is because the period only depends on the length of the pendulum and the acceleration of gravity.

So I would like to get a second opinion please!!!!! =)

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2nd problem:

Warren's answer was FALSE for the statement:
--The wavelength produced by a violin string with a frequency of 196 Hz is GREATER than the wavelength produced by a piano string with a frequency of 262 Hz.

Why? ...... wave speed (e.g., 340 m/s) = wavelength * frequency
So a high frequency would have a short wavelength so the product will = 340 m/s.

Correct?

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3rd problem:

Warren's answer was TRUE for the statement:
--When the crests of two waves overlap the result is DESTRUCTIVE interference

My textbook says: "When the crest of one wave overlaps the crest of another, their individual effects add together. The result is a wave of increased amplitutude. This is called CONSTRUCTIVE interference."

With that said, my answer is FALSE.

I NEED TO FINISH HIGH SCHOOL THIS YEAR AND I'M BEHIND!!!!!

THANKS!!!!!

1. Homework Statement

2. Homework Equations

3. The Attempt at a Solution
1. Homework Statement

2. Homework Equations

3. The Attempt at a Solution