
Answer:
Tension  (T) =  72.126 N
Explanation:
the speed of the pulse is v = 4 (2L)/t = Â 8L/t
8 x4.15/0.900 = Â 33.2/0.900 = 36.89 m/s
The mass density of the cord is d = m/L = 0.220/4.155 = 0.053 kg/m
The tension in the cord is T = d x the square of v
there fore, Â T = 0.053 x 36.89 x 36.89 = 72.126N