Physics Formal Report

Memebers: ACEDO, Rody Mae AGUILAR, Aura Jarrell

Group 2

Date Performed: August 16, 2011

Yr. & Sec.: 2B-MT

Date Submitted: September 6, 2011

ALCID, Ma. Arabella Jaffna ALLAN, Kristen Aljulin ARELLANO, Geo Carlo *AUSTRIA, Adam Leonard

Experiment No. 6 Resonance: The Speed of Sound Abstract:

The speed of sound is the velocity of sound through a mechanical (elastic) medium (such as air, water, concrete, etc.). In fluid dynamics, the speed of sound in a fluid medium (gas or liquid) is used as a relative measure of speed itself. In this experiment, a rubber mallet and a tuning fork was used. The vibrating fork was then placed in a medium partially filled with water. The amount of water was critical in determining the speed of sound. Too much or too low of a water level will not produce a sound. The speed of sound obtained in this experiment was then compared to the actual speed of sound which is 343.2 m/s

Question and Answer: 1. Through what fraction of a vibration has the prong of a tuning fork moved while the sound travelled down to the water surface inside the pipe and reflected back up to the fork again? The prong of the tuning fork vibrated ½ of a cycle it is because the sound wave travelled ¼ down the pipe and another ¼ up again.

2. What is the approximate wavelength of the fundamental frequency of a closed tube 35.0cm long if the tube has a diameter of 4.000cm? Using the formula λ = 4L, let L be the wavelength and L be the length of the tube, therefore: λ = 4(L + 0.3D) λ = 4[35.0 + 0.3(4.000)] 4(36.2) = 144.8 = 145 cm

3.

A tuning fork of frequency 384 Hz exhibits resonance with a closed tube 20.0 cm long and 4.000 cm in diameter. What is the speed of the sound wave? We can get the speed of the sound wave by using the formula V = λf, but first we need to get the wavelength by using λ = 4L therefore: λ = 4(L + 0.3D) λ = 4[20.0 + 0.3(4.000)] λ = 84.8 cm Now we can get the speed of the sound wave: V = λf V = 84.8cm(384Hz) = 32563.2 cm/s We now convert cm/s to m/s: 32563.2cm X 0.01 m = 325.632 m/s s 1cm V = 326 m/s