Answer:
The tension on string when the speed was raised is 134.53 N
Explanation:
Given;
Tension on the string, T = 120 N
initial speed of the transverse wave, v₁ = 170 m/s
final speed of the transverse wave, v₂ = 180 m/s
The speed of the wave is given as;

where;
μ is mass per unit length

The final tension T₂ will be calculated as;

Therefore, the tension on string when the speed was raised is 134.53 N