Answer:
-A.
Explanation:
: Hope it's Help:
[correct me if I'm not correct]
Explanation:
In vector geometry, the resultant vector is defined as: “A resultant vector is a combination or, in simpler words, can be defined as the sum of two or more vectors which has its own magnitude and direction.”
I hope it's helpful!
A) 
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:

Using (2) we can rewrite this as

And using (1), we find

Substituting
into the last equation, we find the value of x:

B) 
In this case, the kinetic energy is 1/10 of the total energy:

Since we have

we can write

And so we find:

Answer:
Explanation:
wavelength, λ = 3.4 m
wavelength, λ' = 3.3 m
Speed, v = 340 m/s
f = v / λ = 340 / 3.4 = 100 Hz
f' = v / λ' = 340 / 3.3 = 103.03 Hz
Frequency of beat, n = f' - f = 103.03 - 100 = 3.03 Hz