For resonance to occur, the object must experience a frequency equal to its

 The correct answer is natural frequency.

Explanation:

Resonance occurs when the applied frequency of the object is equal to its natural frequency.

For example, the soldiers are told not to march on the bridge because the applied frequency on the bridge is equal to the natural frequency of the bridge. The bridge will collapse as resonance occurs in this case.

Therefore, for resonance to occur, the object must experience a frequency equal to its natural frequency.

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50