Answer:
The contribution of the wavelets lying on the back of the wave front is zero because of something known as the Obliquity Factor. It is assumed that the amplitude of the secondary wavelets is not independent of the direction of propagation, Sources: byju's.com
First let us assign variables,
d = distance travelled
t = time it took
v = velocity of the commercial airline
In linear physics, the equation for velocity is given as:
v = d / t
Rewriting for d:
d = v t
We know that the distance to and from south America are equal
therefore:
d1 (going) = d2 (return)
Let us say that velocity of air is v3. Since going to South
America, the wind is against the direction of the plane and the return trip is
the opposite, therefore:
(v1 - v3) t1 = (v1 + v3) t2
(v1 – v3) 4 = (v1 + v3) 3.53
4 v1 – 4 v3 = 3.53 v1 + 3.53 v3
0.47 v1 = 7.53 v3
v1 = 16.02 v3
Since we also know that:
(v1 - v3) t1 = 784
(16.02 v3 – v3) * 4 = 784
60.085 v3 = 784
v3 = 13.05 mph
Therefore the speed of the plane in still air, v1 is:
v1 = 16.02 * 13.05
<span>v1 = 209.03 mph (ANSWER)</span>
<span> </span>
To solve this problem we will apply the concepts of linear mass density, and the expression of the wavelength with which we can find the frequency of the string. With these values it will be possible to find the voltage value. Later we will apply concepts related to harmonic waves in order to find the fundamental frequency.
The linear mass density is given as,
The expression for the wavelength of the standing wave for the second overtone is
Replacing we have
The frequency of the sound wave is
Now the velocity of the wave would be
The expression that relates the velocity of the wave, tension on the string and linear mass density is
The tension in the string is 547N
PART B) The relation between the fundamental frequency and the 
harmonic frequency is
Overtone is the resonant frequency above the fundamental frequency. The second overtone is the second resonant frequency after the fundamental frequency. Therefore
Then,
Rearranging to find the fundamental frequency
The radio waves have a very low frequency so they will always have a very low energy.
Good luck :)
Answer:
Chief Hopper
Explanation:
Mike travels at a constant speed of 3.1 m/s. To find how long it takes him to reach the school, we need to find the distance he travels. We can do this using Pythagorean theorem.
a² + b² = c²
(1000 m)² + (900 m)² = c²
c ≈ 1345 m
So the time is:
v = d / t
3.1 m/s = 1345 m / t
t ≈ 434 s
Next, Chief Hopper travels a total distance of 1900 m, starting at rest and accelerating at 0.028 m/s². So we can use constant acceleration equation to find the time.
d = v₀ t + ½ at²
1900 m = (0 m/s) t + ½ (0.028 m/s²) t²
t ≈ 368 s
So Chief Hopper reaches the school first, approximately 66 seconds before Mike does.
