To develop this problem it is necessary to apply the concepts related to Wavelength, The relationship between speed, voltage and linear density as well as frequency. By definition the speed as a function of the tension and the linear density is given by

Where,
T = Tension
Linear density
Our data are given by
Tension , T = 70 N
Linear density , 
Amplitude , A = 7 cm = 0.07 m
Period , t = 0.35 s
Replacing our values,



Speed can also be expressed as

Re-arrange to find \lambda

Where,
f = Frequency,
Which is also described in function of the Period as,



Therefore replacing to find 


Therefore the wavelength of the waves created in the string is 3.49m
50/200×100%=25% is answer the formula is usefull energy output divided by total energy provided into 100%
"the field of force surrounding a body of finite mass in which anotherbody would experience an attractive force that is proportional to theproduct of the masses and inversely proportional to the square of thedistance between <span>them."
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Answer: C
Explanation:
Find the acceleration using this kinematic equation:

Now use this kinematic equation to find the displacement:
