A wave has a wavelength of 5 meters and a frequency of 4 hertz. What is the speed of the wave? (PLEASE HELP)
Answers
Answer:
The speed of the wave is
15
m
s
.
Explanation:
There are 2 ways to help with this. Explain the details, which are fairly simple in this topic, or give the formula. My hope is that an explanation will last longer than memorizing the formula. I give you both.
If a wave has frequency, f, of 3 Hz, its period, T, is
1
3
s
. The wavelength,
λ
, is 5 meters. That means that in the time of one period, the wave travels 5 m.
In general,
S
p
e
e
d
=
distance
time
In applying this general definition of speed
↑
to a wave, we have
speed of the wave
=
wavelength
period
Note: we generally use v for speed of a wave. Using the variable names, then that last formula is written
v
=
λ
T
Since
T
=
1
f
, we can also say that
v
=
λ
⋅
f
So, using that last formula
v
=
5
m
⋅
3
H
z
=
15
m
s
Note: the unit Hz is equivalent to what it was called 100 years ago,
cycles
second
(
also cps
)
. Cycles is not a true unit, so the Hz contributed only the "per second" to the result
15
m
s
.