• Экзамен / Домашнее задание

  • Экзамен / Домашнее задание

    • 23. - 29. Март

      Класс:
      Тип:
      • Пн23. 03.
      • 11-A KG
        ·
        Назначено домашнее задание
        History
        :
        Параграф 21. "Кайра куруу" жылдарындагы Кыргызстан (1985 - 1990-жж.).
      • 8-C
        ·
        Назначено домашнее задание
        Инсандык онугуу
        :
        эссе
      • 9-A
        ·
        Назначено домашнее задание
        Russian Language
        :
        Трениров.упр
      • 9-C
        ·
        Назначено домашнее задание
        Kyrgyz Literature
        :
        "Жеңишбек" поэмасын маанисин өзгөртпөй заманбап түрдө жазып келүү.
      • Вт24. 03.
      • 11-B
        ·
        домашнее задание
        Physics
        :
        8.8 The Doppler Effect 1. What is the Doppler Effect? The Doppler Effect is the change in observed frequency of a wave due to relative motion between the source and the observer. ________________________________________ 2. What is meant by Doppler shift? Doppler shift is the change in frequency between the emitted wave and the observed wave. ________________________________________ 3. When is the Doppler Effect observed? It is observed when there is relative motion between the source and the observer along the line between them. ________________________________________ 4. Does the Doppler Effect apply only to sound waves? No, it applies to all waves, including sound, light, and electromagnetic waves. ________________________________________ 5. What happens to the pitch of a sound as a source approaches an observer? The pitch (frequency) increases. ________________________________________ 6. What happens to the pitch as the source moves away? The pitch (frequency) decreases. ________________________________________ Understanding the Cause 7. Why are wave fronts closer together in front of a moving source? Because the source is moving in the same direction as the waves, causing them to bunch up. ________________________________________ 8. Why are wave fronts spread out behind a moving source? Because the source is moving away from the waves, increasing the distance between them. ________________________________________ Frequency and Wavelength 9. What is the relationship between wave speed, frequency, and wavelength? Wave speed = frequency × wavelength (v = fλ). ________________________________________ 10. What happens to wavelength ahead of the source? The wavelength decreases. ________________________________________ 11. What happens to frequency ahead of the source? The observed frequency increases. ________________________________________ 12. What happens to wavelength behind the source? The wavelength increases. ________________________________________ 13. What happens to frequency behind the source? The observed frequency decreases. ________________________________________ Doppler Effect Equations 14. What is the formula for observed frequency when the source is moving? f′=v/v∓vs f Where: • f' = observed frequency • f = source frequency • v = wave speed • vs = speed of the source ________________________________________ 15. Which sign is used in the Doppler equation? • Use minus (−) when the source is moving towards the observer • Use plus (+) when the source is moving away from the observer ________________________________________ 16. Why is the observed frequency higher when the source approaches? Because the wavelength is shorter, so more waves reach the observer per second. ________________________________________ 17. Why is the observed frequency lower when the source moves away? Because the wavelength is longer, so fewer waves reach the observer per second. ________________________________________ Doppler Shift 18. What is the expression for Doppler shift? Δf=f′−f ________________________________________ 19. What happens to Doppler shift when the source approaches? The shift is positive (frequency increases). ________________________________________ 20. What happens when the source moves away? The shift is negative (frequency decreases). ________________________________________ Applications of the Doppler Effect 21. How is the Doppler Effect used in speed cameras? Radar emits microwaves that reflect off vehicles; the change in frequency of the reflected waves is used to calculate speed. ________________________________________ 22. What is a Doppler anemometer? A device that uses laser light to measure wind speed using Doppler shift. ________________________________________ 23. What is Doppler echocardiography? A medical technique using ultrasound to measure blood flow speed and direction in the heart. ________________________________________ Worked Example Concepts 24. What is the speed of sound in air (used in calculations)? Approximately 340 m/s. ________________________________________ 25. How do you calculate wavelength? λ=v/f ________________________________________ 26. How do you calculate observed frequency? By substituting values into the Doppler equation. ________________________________________ 1a. Calculate the frequency heard by an observer when the car approaches. Given: • Speed of sound, v=340 m/s • Speed of car, vs=28 m/s • Source frequency, f=1100 Hz • Formula: f′=v/v−vsf f′=340/340−28 ×1100=340/312 ×1100≈1.09×1100≈1199 Hz Answer: ≈ 1200 Hz ________________________________________ 1b. what frequency is heard when the car is directly below the bridge? Explain. Answer: The frequency heard is 1100 Hz (the original frequency) because there is no motion towards or away from the observer at that instant, so there is no Doppler shift. ________________________________________ 2a. Is the train moving towards X or Y? Explain. Answer: The train is moving towards Y because the observer at Y hears a higher frequency, while the observer at X hears a lower frequency. This means the train is moving away from X and towards Y. ________________________________________ 2b. Calculate the emitted frequency of the horn. Given: • f′=950 Hz (heard at X, moving away) • v=340 m/s • vs=40 m/s • Formula (moving away): f′=v/v+vs f 950=340/340+40 f=340/380 f f=950×380/340≈950×1.118≈1062  Answer: ≈ 1060 Hz ________________________________________ 3a. Calculate the speed of rotation at the Sun’s equator. Given: • Diameter = 1.4×109 m • Radius = 0.7×109 m • Time = 25 days = 25×24×3600=2.16×106 s Circumference: 2πr=2π(0.7×109)≈4.4×109 m Speed: V = distance/time=4.4×109 / 2.16×106≈2037 m Answer: ≈ 2.0 × 10³ m/s ________________________________________ 3b. Calculate the change in frequency (Doppler shift). Given: • v=3.0×108 m • vs=2.0×103 m/s • f=5.0×1014 Hz Formula: Δf=vs/ Δf=2.0×103 / 3.0×108 ×5.0×1014 =2/3×10−5×5.0×1014≈3.3×109 Hz Answer: ≈ 3.3 × 10⁹ Hz (decrease, since moving away) ________________________________________ 4a. Why is ultrasound unsuitable for a Doppler anemometer? Answer: Ultrasound requires a material medium (like air) and is easily absorbed or scattered, making it less accurate for precise measurements over distances. ________________________________________ 4b. Why are microwaves unsuitable instead of laser light? Answer: Microwaves have a longer wavelength, so they are less precise and cannot detect small particles as effectively as laser light.
      • 11-B RU
        ·
        домашнее задание
        Russian Literature
        :
        знать о жизни и творчестве писателя; опереж. зад. "И дольше века длится день"
      • 11-B, 11-A, 11-D KG
        ·
        домашнее задание
        Russian Literature
        :
        Анализ произведения
      • 11-D RU
        ·
        Назначено домашнее задание
        ОРТ РУССКИЙ ЯЗЫК
        :
        Имя прилагательное
      • 11-D, 11-A RU
        ·
        домашнее задание
        Russian Literature
        :
        знать о жизни и творчестве писателя; опереж. зад. "И дольше века длится день"
      • 7-B
        ·
        домашнее задание
        Mathematics
        :
        CB Ex 9.2
      • 7-С
        ·
        домашнее задание
        Russian Language
        :
        Стр.185 упр. 318
      • 8-A
        ·
        Назначено домашнее задание
        Russian Language
        :
        Упр. 250
      • 8-D
        ·
        домашнее задание
        Mathematics
        :
        CB Ex 12.1
      • 9-A
        ·
        домашнее задание
        Mathematics
        :
        page 311-312
      • 9-A
        ·
        домашнее задание
        Russian Literature
        :
        Помещики
      • 9-B
        ·
        домашнее задание
        Mathematics
        :
        page 311-312
      • 9-C
        ·
        домашнее задание
        English
        :
        повторение
      • 9-C
        ·
        домашнее задание
        Mathematics
        :
        page 311-312
      • 9-D
        ·
        домашнее задание
        Russian Literature
        :
        "БЭЛА" анализ
      • Ср25. 03.
      • 10-A
        ·
        домашнее задание
        Russian Language
        :
        Зачёт ,упр
      • 10-B
        ·
        домашнее задание
        Russian Literature
        :
        доработать эссе ; опереж. зад.по роману Н. Г. Чернышевского " Что делать?"
      • 11-B RU
        ·
        домашнее задание
        Russian Literature
        :
        знать сюжет, тему, идею и героев романа
      • 11-C
        ·
        домашнее задание
        Physics
        :
        8.8 The Doppler Effect 1. What is the Doppler Effect? The Doppler Effect is the change in observed frequency of a wave due to relative motion between the source and the observer. ________________________________________ 2. What is meant by Doppler shift? Doppler shift is the change in frequency between the emitted wave and the observed wave. ________________________________________ 3. When is the Doppler Effect observed? It is observed when there is relative motion between the source and the observer along the line between them. ________________________________________ 4. Does the Doppler Effect apply only to sound waves? No, it applies to all waves, including sound, light, and electromagnetic waves. ________________________________________ 5. What happens to the pitch of a sound as a source approaches an observer? The pitch (frequency) increases. ________________________________________ 6. What happens to the pitch as the source moves away? The pitch (frequency) decreases. ________________________________________ Understanding the Cause 7. Why are wave fronts closer together in front of a moving source? Because the source is moving in the same direction as the waves, causing them to bunch up. ________________________________________ 8. Why are wave fronts spread out behind a moving source? Because the source is moving away from the waves, increasing the distance between them. ________________________________________ Frequency and Wavelength 9. What is the relationship between wave speed, frequency, and wavelength? Wave speed = frequency × wavelength (v = fλ). ________________________________________ 10. What happens to wavelength ahead of the source? The wavelength decreases. ________________________________________ 11. What happens to frequency ahead of the source? The observed frequency increases. ________________________________________ 12. What happens to wavelength behind the source? The wavelength increases. ________________________________________ 13. What happens to frequency behind the source? The observed frequency decreases. ________________________________________ Doppler Effect Equations 14. What is the formula for observed frequency when the source is moving? f′=v/v∓vs f Where: • f' = observed frequency • f = source frequency • v = wave speed • vs = speed of the source ________________________________________ 15. Which sign is used in the Doppler equation? • Use minus (−) when the source is moving towards the observer • Use plus (+) when the source is moving away from the observer ________________________________________ 16. Why is the observed frequency higher when the source approaches? Because the wavelength is shorter, so more waves reach the observer per second. ________________________________________ 17. Why is the observed frequency lower when the source moves away? Because the wavelength is longer, so fewer waves reach the observer per second. ________________________________________ Doppler Shift 18. What is the expression for Doppler shift? Δf=f′−f ________________________________________ 19. What happens to Doppler shift when the source approaches? The shift is positive (frequency increases). ________________________________________ 20. What happens when the source moves away? The shift is negative (frequency decreases). ________________________________________ Applications of the Doppler Effect 21. How is the Doppler Effect used in speed cameras? Radar emits microwaves that reflect off vehicles; the change in frequency of the reflected waves is used to calculate speed. ________________________________________ 22. What is a Doppler anemometer? A device that uses laser light to measure wind speed using Doppler shift. ________________________________________ 23. What is Doppler echocardiography? A medical technique using ultrasound to measure blood flow speed and direction in the heart. ________________________________________ Worked Example Concepts 24. What is the speed of sound in air (used in calculations)? Approximately 340 m/s. ________________________________________ 25. How do you calculate wavelength? λ=v/f ________________________________________ 26. How do you calculate observed frequency? By substituting values into the Doppler equation. ________________________________________ 1a. Calculate the frequency heard by an observer when the car approaches. Given: • Speed of sound, v=340 m/s • Speed of car, vs=28 m/s • Source frequency, f=1100 Hz • Formula: f′=v/v−vsf f′=340/340−28 ×1100=340/312 ×1100≈1.09×1100≈1199 Hz Answer: ≈ 1200 Hz ________________________________________ 1b. what frequency is heard when the car is directly below the bridge? Explain. Answer: The frequency heard is 1100 Hz (the original frequency) because there is no motion towards or away from the observer at that instant, so there is no Doppler shift. ________________________________________ 2a. Is the train moving towards X or Y? Explain. Answer: The train is moving towards Y because the observer at Y hears a higher frequency, while the observer at X hears a lower frequency. This means the train is moving away from X and towards Y. ________________________________________ 2b. Calculate the emitted frequency of the horn. Given: • f′=950 Hz (heard at X, moving away) • v=340 m/s • vs=40 m/s • Formula (moving away): f′=v/v+vs f 950=340/340+40 f=340/380 f f=950×380/340≈950×1.118≈1062  Answer: ≈ 1060 Hz ________________________________________ 3a. Calculate the speed of rotation at the Sun’s equator. Given: • Diameter = 1.4×109 m • Radius = 0.7×109 m • Time = 25 days = 25×24×3600=2.16×106 s Circumference: 2πr=2π(0.7×109)≈4.4×109 m Speed: V = distance/time=4.4×109 / 2.16×106≈2037 m Answer: ≈ 2.0 × 10³ m/s ________________________________________ 3b. Calculate the change in frequency (Doppler shift). Given: • v=3.0×108 m • vs=2.0×103 m/s • f=5.0×1014 Hz Formula: Δf=vs/ Δf=2.0×103 / 3.0×108 ×5.0×1014 =2/3×10−5×5.0×1014≈3.3×109 Hz Answer: ≈ 3.3 × 10⁹ Hz (decrease, since moving away) ________________________________________ 4a. Why is ultrasound unsuitable for a Doppler anemometer? Answer: Ultrasound requires a material medium (like air) and is easily absorbed or scattered, making it less accurate for precise measurements over distances. ________________________________________ 4b. Why are microwaves unsuitable instead of laser light? Answer: Microwaves have a longer wavelength, so they are less precise and cannot detect small particles as effectively as laser light.
      • 11-C
        ·
        домашнее задание
        Russian Literature
        :
        знать сюжет, тему, идею и героев романа
      • 7-A
        ·
        домашнее задание
        Russian Language
        :
        Упр 338
      • 7-С
        ·
        домашнее задание
        Kyrgyz Language
        :
        Кайталоо
      • 8-C
        ·
        домашнее задание
        Mathematics
        :
        12.3 examples from 1 to 6
      • 9-B
        ·
        домашнее задание
        History
        :
        Глава 4. Кыргызстан в годы Великой Отечественной войны (1941 - 1945 гг.). Параграф 13. Воины Кыргызстана на полях сражений Великой Отечественной войны (1941 - 1945 гг.) .
      • Чт26. 03.
      • 10-B
        ·
        домашнее задание
        Kyrgyz Language
        :
        "Ийгиликке жетүүнүн сырлары" каалаган мугалимден интервью алып төл жана бөтөн сүйлөмдөр түрүндө жазып келүү( 10 сүйлөм)
      • 10-B
        ·
        домашнее задание
        Russian Language
        :
        параграф 46,стр.168,упр.259
      • 11-C
        ·
        домашнее задание
        Russian Language
        :
        параграф 83,стр. уч 305. ,упр.451 ,
      • 11-D, 11-A RU
        ·
        домашнее задание
        Russian Literature
        :
        знать сюжет, тему, идею и героев романа
      • 7-B
        ·
        домашнее задание
        Russian Language
        :
        Стр.185 упр. 318
      • 8-B
        ·
        домашнее задание
        Geography
        :
        п.34
      • 8-C
        ·
        домашнее задание
        Geography
        :
        п.34
      • 8-C
        ·
        домашнее задание
        Russian Literature
        :
        "Фотография на которой меня нет." прочитать
      • Пт27. 03.
      • 11-B RU
        ·
        домашнее задание
        Russian Language
        :
        параграф 83,стр.305-310
      • 8-C
        ·
        домашнее задание
        History
        :
        Глава 6. Национально-освободительное движение народов Восточного Теңир-Тоо против Цинской империи. Параграф 15. Восстание дунган в провинциях Ганьсу, Шэньси и Синьцзян. Джакып-бек и его государство Джети-шаар (Семиградье).
      • 9-C
        ·
        домашнее задание
        Geography
        :
        п.23