1) c. 2 m/s
Explanation:
The relationship between frequency, wavelength and speed of a wave is

where
v is the speed
is the wavelength
f is the frequency
For the wave in this problem,
f = 4 Hz

So, the speed is

2) a. 2.8 m/s
The speed of the wave on a string is given

where
T is the tension in the string
is the linear mass density
In this problem, we have:
(final tension in the rope, which is twice the initial tension)
--> mass density of the rope
Substituting into the formula, we find

The mass of a is smaller than the mass of b.
Answer:
A. The resonator behaves as a wave guide (a hollow pipe used as a transmission line). The characteristics of the pipe depend on the type of the wave to be transmitted.
Answer:
16.96 W
Explanation:
Power: This can be defined as the rate at which work is done by an object. The S.I unit of power is Watt(W).
From the question,
P = (F×d)/t....................... Equation 1
Where P = power, F = force, d = distance, t = time.
Given: F = 75 N, d = 42 m, t = 3.1 min = 3.1×60 = 186 s
Substitute these values into equation 1
P = (75×42)/186
P = 16.94 W
Hence the average power delivered by the child = 16.96 W
Answer:

What is the humidity if the dry-bulb is 10℃ and the wet-bulb is 6℃?
<h2><u>33% According to the Graph</u></h2>
Hope this helps!