Shoo the fly flaps its wings back and forth 140 times each second. The frequency of the wing flapping is Hz.

140 Hz

Explanation:

Frequency is the reciprocal of period hence f=1/T

Here, the frequency is 140 times per second hence the period will be 1/140= 0.0071428571428 s

Rounded off to 3 significant figures then the period is 0.00714 s or 0.714 ms

Otherwise, the frequency is already given as 140 cycles per second which is equivalent to 140 Hz

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.