Chemistry, 03.02.2020 21:57 xczapien782
Which of the following statements is true of vibrations? a. the frequency of infrasonic vibrations is much too high to be heard by humans. b. infrasonic vibrations are used in sonar equipment and to detect flaws in steel castings. c. ultrasonic vibrations have a frequency lower than the range for normal hearing. d. neither ultrasonic nor infrasonic vibrations can be heard by humans
Answers: 1
Chemistry, 21.06.2019 23:30
Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.
Answers: 2
Chemistry, 22.06.2019 07:00
Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li
Answers: 1
Chemistry, 22.06.2019 12:00
Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.
Answers: 2
Which of the following statements is true of vibrations? a. the frequency of infrasonic vibrations...
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