Which of the following statements is an accurate description of vibrations? a. ultrasonic vibrations have a frequency lower than the range for normal hearing. b. infrasonic vibrations are used in sonar equipment as well as to detect flaws in steel castings. c. the frequency of infrasonic vibrations is much too high to be heard by humans. d. neither ultrasonic nor infrasonic vibrations can be heard by humans.

The correct answer is option D. "Neither ultrasonic nor infrasonic vibrations can be heard by humans".

Explanation:

Ultrasonic vibrations are high-frequency sound waves produced by frequencies above 20,000 hertz. On the other hand, infrasonic vibrations are sound waves whose frequency is below about 20 hertz. Neither ultrasonic nor infrasonic vibrations can be heard by humans because the sound waves produced by the frequencies are beyond the range of human hearing.

weather forecasts are done by collecting data about the current state of the atmosphere mainly the temperature, humidity and wind and using meteorology, to determine the atmosphere that evolves over time. the h and l mean the high and low pressure. the red strip is a warm front. the blue strip is a cold front. the blue and red strip is a stationary front. the purple strip is a occluded front.

explanation:

6 cos 34, 6 sin 34 trig