Answer:
a) and c).
Explanation:
For a complete destructive interference occur, it must be met the following condition relating the wavelength, and the difference in the paths taken by the sound emitted by the sources until arriving to the listening point:
d = |dA- dB| = (2n-1)*(λ/2)
For n= 1, d = λ/2 = 0.25 m, it doesn't meet any of the cases.
For n=2, d= 3*(λ/2) = 0.75 m
In the case a) we have dA = 2.15 m and dB = 3.00 m, so dB-dA = 0.75 m, which means that in the location stated by case a) a complete destructive interference would occur.
For n=3, d= 5*(λ/2) = 5*0.25 m = 1.25 m.
This is just the case c) because we have dA = 3.75 m and dB = 2.50 m, so dA-dB = 1.25 m, which means that in the location stated by case c) a complete destructive interference would occur also.
The remaining cases don't meet the condition stated above, so the statements found to be true are a) and c),
The terminal speed of the marble is 0.588 m/s.
<h3>Calculation:</h3>
We know that,
F = mg ......(1)
where,
F = force
m = mass
g = acceleration due to gravity
Also,
v = F/k ......(2)
where,
v = terminal speed
k = proportionality constant
Substituting the value of F from equation (1) in equation (2)
v = mg/k .......(3)
Given,
m = 30 g = 0.030 kg
k = 0.500 kg/s
g = 9.8 m/s²
To find,
v =?
Put the values in equation (3)
v = mg/k
v = 0.03(9.8)/ 0.500
= 0.294/0.500
= 0.588 m/s
Hence, the terminal speed of the marble is 0.588 m/s.
Learn more about calculation of force here:
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.
Answer:
d
Explanation:
because is a reducing agent, O 2 is an oxidizing agent.
No because it is dense and opaque
Answer:
b. (4677)
Explanation:
You can apply the same equation we use to calculate the compound interest but with phones.
Look:
M = C.(1+i)^n
M = the total amount after 5 years
C = the firts amout of phones (285)
i = how much this number gets bigger (75%)
n = the number of periods (5 years)
So...
M = 285 . (1 + 0,75)^5
M = 285 . 1,75^5
M = 285 . 16.4
M = 4677