On a nice summer day when the temperature is 23 C, you purse your lips and whistle across the top of an empty pop bottle that is 29 cm tall and has NO BOTTOM. What must be the frequency of your whistle to make the air in the bottle vibrate in the fourth resonant length?vibrational cycles in 20 seconds. Determine the frequency, period, wavelength and speed for this wave.​

Asmall metal bar, whose initial temperature was 10° c, is dropped into a large container of boiling water. how long will it take the bar to reach 70° c if it is known that its temperature increases 2° during the first second? (the boiling temperature for water is 100° c. round your answer to one decimal place.) sec how long will it take the bar to reach 98° c? (round your answer to one decimal place.)

Using a pedometer, you walk 3000 steps in 20 minutes, so your speed is 150 steps/min. each of your steps is 0.7 m long. what is your speed? 150 steps/min=/s=/h

Chemical energy is a form of energy. a. heat b. kinetic c. potential d. electromagnetic