Physics of Music Explain how a trombone works

Physics of Music • Explain how a trombone works in terms of the physics of waves.

• Galloping Gertie • Rice Resonance

• What will we hear if I play two tones that have slightly different frequencies? • Beats – When the sound changes in volume periodically due to the interference of the waves.

2 D Interference • Sound • Water

Review

If the force of friction on the box is 50 N, how hard must someone pull the box up the ramp in order to get it to move at a constant velocity? What is the coefficient of friction? FN Angle of elevation is 20° mbox= 27 kg Fp Fk Fg

FN x y 0 FN Fg Fp Fk Ffs -50 0 Fp F 1 0 0 0 Fg Fp = 140. 5 N FN = 248. 6 N

What’s the tension in each string if the bob has a mass of 8 kg? T 2 40 T 1 Fg T 2

T 2 Fg= 78. 4 N T 2 y= 78. 4 N T 2= 102. 3 N T 2 x= T 1 T 1= 65. 8 N Fg

Kinematic Equations for Constant Acceleration x x 0 X X X v v 0 t a X X X X

Graph Meaning of Slope Meaning of yintercept Position vs. time Velocity Initial position Velocity vs. time Acceleration Initial velocity Meaning of area under the curve Change in position (Displacement, Δx) Change in velocity, Δv

Velocity vs. Time Graphs • Above the time axis: moving forward • Below the time axis: moving backwards

Velocity vs. Time Graphs v • Going towards the time axis: slowing down • Going away from the time axis: speeding up t v t

*Concavity of x-t graphs* x x x Positive acceleration Concave up Negative acceleration Concave down x