Chapter 10 Numerical Problems Examples
Example 10.2: A wave moves on a slinky with frequency of 4Hz and wavelength of 0.4 m. What is the speed of the wave?
Solution:
Given that, f = 4 Hz, ฮป = 0.4 m
Wave speedย v = f ฮป
v = (4 Hz) (0.4 m)
v = 1.6 m s-1
Example 10.3: A student performs an experiment with waves in water. The student measures the wavelength of a wave to be 10 cm. By using a stopwatch and observing the oscillations of a floating ball, the student measures a frequency of 2 Hz. If the student starts a wave in one part of a tank of water, how long will it take the wave to reach the opposite side of the tank 2 m away?
Solution:
(1) We are given the frequency, wavelength, and distance.
(2) We have to calculate the time, the wave takes to move a
distance of 2 m.
(3) The relationship between frequency, wavelength, and speed is
v = f ฮป. The relationship between time, speed, and distance is
v = d /t
(4) Rearrange the speed formula to solve for the time: t = d / v
The speed of the wave is the frequency times the wavelength.
v = f ฮป = (2 Hz)(0.1 m) = 0.2 m s-1 .
Use this value to calculate the time:
t = 2 m/0.2 m s-1 = 10s
<—————————–>