Answer:
434 Hz
Explanation:
According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.
In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.
The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.
Answer:
I think it's 0 N 3rd choice
Answer:
a♦1 E_average = n E₀ / 2
, b) E_average= infinity
Explanation:
The energy values form an arithmetic series, whose sum is
S = n (a₁ + aₙ) / 2 = n (2a₁ + (n-1) r)/ 2
Where n is the number of terms, a₁ is the first term, aₙ the last term and r is the difference between two consecutive numbers in the series
r = 2E₀ - 0 = 2E₀
Therefore the sum is
S = n (0 + n E₀) / 2
S = n² E₀ / 2
The average value is
E_average = S / n
E_average = n E₀ / 2
b) the case of harmonic oscillation
We have two possibilities.
- if we take a finite number and terms gives the same previous value
- If we take an infinite number of fears the series gives infinity and the average is also infinite
E_average= infinity
