P09_Waves

Old Dominion University Physics 111/226/231/261 Lab Manual 3 The linear density (mass per unit length) of the string is found by: σ = M L (5) where M is the mass of the string in kilogram, and L is the length of the string in meter. Procedure In this experiment, you will use a frequency generator (Pasco Digital Function Generator) to drive a speaker that vibrates one end of a string. The other end of the string passes over a pulley and has a slotted mass hanging from it to provide tension in the string. The tension ( F ), in Equation (1) is the weight (in Newton) of the slotted mass ( m ), hanging from the string. The linear density ( σ ) is in kilogram/meter (kg/m). For standing waves on a string, the wavelength ( ), is twice the distance λ between nodes ( = 2d). λ  Equipment Setup 1. Measure the length of the elastic wave string. ( Note: all knots must be removed!) Use a digital scale to measure the mass of the elastic wave string. Record the values in Data Table 2. 2. Take the large C-shaped clamp and use it to secure the String Vibrator to the table. There is even a spot on the vibrator that says, “Clamp Here”. 3. Plug one red and one black banana-banana cable into the red/black ports on the Function Generator and then plug the other end into the string vibrator. 4. Attach the Pulley table clamp to the opposite edge of the lab table. 5. a) Tie a small loop on the end of the elastic wave string hanging over the pulley assembly. b) Attach a 50 g mass hanger to the elastic wave string hanging over the pulley. Then add 450 grams to the hanger. Figure P09.2: Pulley Figure P09.1: String Vibrator

6 Experiment P09: Waves Data Table – Experiment P09 Data Table 1 Standing Waves on a String Harmonic (# Anti-nodes) H Distance Between Nodes d n Sum of d n = d tot Average Distance Between Nodes (m) Frequency of Harmonic f (Hz) Wavelength of Harmonic λ = 2 d ave (m) Velocity of the Wave v = fλ (m/s) 1 m 2 m m 3 m m m 4 m m m m 5 m m m m m 6 m m m m m m 7 m m m m m m m 8 m m m m m m m m 9 m m m m m m m m m 10 m m m m m m m m m m Data Table 2