"b. The nucleus is made of
protons and neutrons and has a positive charge" is the only option that is true about the atomic nucleus. The protons give it a positive charge.
Answer:

Explanation:
We know that the frequency of the nth harmonic is given by
, where
is the fundamental harmonic. Since we have the values of two consecutive frequencies, we can do:

Which for our values means (we do not need the value of <em>n</em>, that is, which harmonics are the frequencies given):

Now we turn to the formula for the vibration frequency of a string (for the fundamental harmonic):

So the tension is:

Which for our values is:

<span>The force would double.</span>
A and C Im pretty sure :)
90+66=156
156/2=78
Reply:78kilometers in 2 hours.