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

answer: i'm not sure which is which for i get confused on it all the time but i can tell you that the answer lies with the convex and concave devices. i hope this you. have a good day and best of luck to you!

explanation:

i guess it’s a and b