This preview shows pages 1–3. 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: PHYS408 Fall 2008 Mastering Physics Assignment #6 Solutions Problem 20.12 The displacement of a wave traveling in the positive xdirection is D ( x, t ) = ( 3.5 (cm) ) sin ( 2.7x124t ), where x is in m and t is in s. (a) What is the frequency of this wave? = 2 f = 124 / s f = 2 = 124 / s 2 = 19.7/ s = 19.7 Hz (b) What is the wavelength of this wave? k = 2 = 2.7/ m = 2 k = 2 2.7/ m = 2.33 m (c) What is the speed of this wave? v = f = 2.33 m ( ) 19.7 Hz ( ) = 45.9 m / s Problem 20.16 (a) A spherical wave with a wavelength of 2.0 m is emitted from the origin. At one instant of time, the phase at r = 4.0 m is pi (rad). At that instant, what is the phase at r =3.5 m? Since time is constant, we can simply ask what is the change in phase: = k x k = 2 = 2 2.0 m = / m x = 3.5 m 4.0 m ( ) = 0.5 m = / m 0.5 m ( ) = 0.5 = f x = 3.5 m ( ) i x = 4.0 m ( ) Where I have labeled the x values to make the initial and final clear. f = i + = 0.5 = 0.5 = 2 (b) What is the phase at r =4.5 m at the same instant? x = 4.5 m 4.0 m ( ) = 0.5 m = / m 0.5 m ( ) = 0.5 f = i + = + 0.5 = 1.5 = 3 2 Problem 20.20 (a) What is the wavelength of a 2.0 MHz ultrasound wave traveling throughWhat is the wavelength of a 2....
View Full
Document
 Spring '08
 BEANE
 Physics

Click to edit the document details