Considering Conservation of Momentum, the momentum

before and after must remain the same:
so:
before:
Answer:
Explanation:
Given
Potential Energy is given by

And Force is given by

Particle will be at equilibrium when Potential Energy is either minimum or maximum

i.e.

So angular Frequency of small oscillation is given by

for 
we get 


True!!!!!!!!!!!!!!!!!!!!!
Explanation:
Given that,
2 strings both vibrate at exactly 220 Hz. The frequency of sound wave depends on the tension in the strings.
The tension in one of them is then decreased sightly, then
will decrese.
Beat frequency, 

So, the new frequency of the string is 217 Hz. Hence, this is the required solution.
Its like newtons 3rd law that once in motion a outer force has to stop it