Wave properties
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calculating frequency
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a hummingbird can flutter its wings 4,800 times per minute.
what is the frequency of wing flutters per second?
flutters/second
what is the period for one wing flutter in seconds?

f = 80  flutter/ second

T= 0.0125 sec

Explanation:

Given data:

Fluttering of wings = 4800 time per minute

Frequency of wings = ?

Period for one wing in sec = ?

Solution:

There are 60 seconds in one minute, thus frequency of wings

4800/60 = 80  flutter per second

Period:

T = 1/f

T = 1/80

T= 0.0125 sec

"the periodic table is arranged in order of atomic number."

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.