Answer:
The frequency of the waves depends on the distance between wave fronts - considering a front as a maximum disturbance of the wave
(Consider the waves emitted by an organ pipe: condensation and rarefactions)
The waves themselves are a fixed distance apart -
as one moves towards the source the waves received will be closer together (higher frequency)
So if the frequency received increases, the distance between the source and the observer must be decreasing
The relationship between the speed, the frequency and the wavelength of a wave is given by:
where
f is the frequency
v is the speed of the wave
is its wavelength
for the pressure wave in this problem,
and v=1400 m/s, therefore its frequency is
We use the binomial theorem to answer this question. Suppose we have a trinomial (a + b)ⁿ, we can determine any term to be:
[n!/(n-r)!r!] a^(r) b^(n-r)
a.) For x⁵y³, the variables are: x=a and y=b. We already know the exponents of the variables. So, we equate this with the form of the binomial theorem.
r = 5
n - r = 3
Solving for n,
n = 3 + 5 = 8
Therefore, the coefficient is equal to:
Coefficient = n!/(n-r)!r! = 8!/(8-5)!8! = 56
b.) For x³y⁵, the variables are: x=a and y=b. We already know the exponents of the variables. So, we equate this with the form of the binomial theorem.
r = 3
n - r = 5
Solving for n,
n = 5 + 3 = 8
Therefore, the coefficient is equal to:
Coefficient = n!/(n-r)!r! = 8!/(8-3)!8! = 56
Answer:
F1 = k Q1 * Q2 / R^2
If Q1 is doubled then F2 = 2 F1 = 72 units
