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 21 Fall, 2011 Solution to HW22 K207 The wave speed on a string under tension is 170 m/s. What is the speed if the tension is doubled? From Eq. (3) in the waves handout, v = p T /ρ, so if the tension T is doubled, v increases by √ 2. K2011 A wave travels with speed 180 m/s. Its wave num ber is 1.40 rad/m. What is its wavelength? What is its frequency? k = 2 π/λ ⇒ λ = 2 π/k = 2 π/ 1 . 40 = 4 . 49 m v = f λ ⇒ f = v/λ = 180 / 4 . 49 = 40 . 1 Hz K2042 This is a snapshot graph at t = 0 of a 5.0 Hz wave traveling to the left. What are the speed and phase constant of the wave? D ( x, t ) = A sin( kx + ωt + φ ) . From the graph, λ = 2 . 0 m, and f = 5 . 0 Hz is given. Hence v = λf = 10 m / s . We already know the graph is at t = 0. At x = 0, the amplitude is abut 0.5. Since the maximum amplitude on the graph is 1, we have . 5 = 1 . 0 sin( k 0 + ω 0 + φ ) = sin φ ⇒ φ = 30 ◦ . K2052 Earthquakes are essentially sound waves trav eling through the earth. They are called seismic waves....
View
Full
Document
This note was uploaded on 12/18/2011 for the course PHYS 021 taught by Professor Hickman during the Spring '08 term at Lehigh University .
 Spring '08
 Hickman
 Work

Click to edit the document details