﻿ Lecture 28 Summary
• Resonance
• Waves
• Wave properties

pse6 16.3
A wave moving along the x-axis is described by
y(x,t) = 5.00e−(x + 5.00t

Determine the direction of motion.
A. +x direction
B. −x direction
C. not moving

pse6 16.3
A wave moving along the x-axis is described by
y(x,t) = 5.00e−(x + 5.00t

Determine the wave speed.
A. 5.00 m/s
B. 6.74 mm/s
C. 10.0 m/s
D. 0 m/s

PoP5 13.19
Transverse waves travel at 20.0 m/s in a string under a tension of 6.00 N. What tension is required for a wave speed of 30.0 m/s in the same string?
A. 2.67 N
B. 4.00 N
C. 9.00 N
D. 13.5 N

klm
A sound wave travels through wood into aluminum, a stiffer medium than wood. Is the reflected wave in the wood inverted?
A. Yes
B. No
C. Can't say

PoP5 13.24
What power must be supplied to a taut rope of mass 0.180 kg and length 3.60 m in order to generate sinusoidal waves of amplitude 0.100 m, wavelength 0.500 m, and speed 30.0 m/s?
A. 427 kW
B. 18.8 kW
C. 1.07 kW
D. 28.3 W

B. −x direction
The positive sign in front of vt in the expression indicates the wave travels in the negative x direction.

A. 5.00 m/s
The number in front of t in the expression is the wave speed in meters per second.

D. 13.5 N

B. No
A wave does not invert when it reflects from a boundary where it is going from a slow medium (wood) into a fast medium (aluminum).