A steel piano string of mass per unit lenght 4*10-⁴kgm-¹ was struck, if the speed of the sound on the string is 300ms-¹. Calculate the tension.

36 N

Explanation:

Velocity of a standing wave in a stretched string is:

v = √ (T/ρ),

where T is the tension and ρ is the mass per unit length.

300 m/s = √ (T / 4*10⁻⁴ kg/m)

T = 36 N