A wave is traveling in a string at 68 m/s.When the tension is then increased 15%,what will be the resulting wave speed?

A) also 68 m/s
B) 73 m/s
C) 63 m/s
D) 26 m/s
E) 78 m/s

Question

A wave is traveling in a string at 68 m/s.When the tension is then increased 15%,what will be the resulting wave speed?
​
A) also 68 m/s
B) 73 m/s
C) 63 m/s
D) 26 m/s
E) ​78 m/s

Quizplus · Accepted Answer

The wave speed in a string is given by the equation v = sqrt(T/μ), where T is tension and μ is mass per unit length. 
Since the tension is increased by 15%, the new tension will be T + 0.15T = 1.15T. 
Plugging this value back into the equation for v, we get v' = sqrt(1.15T/μ). 
Since mass per unit length of the string doesn't change, the new wave speed will be 1.15 times the original wave speed, which is 1.15*68 m/s = 78.2 m/s, which is approximately equal to 73 m/s. Thus, choice B is the best answer.

A Wave Is Traveling in a String at 68 M/s