A string of length 40 cm and weighing 10 g is attached to a spring at one end and to a fixed wall at the other end. The spring has a spring constant of `160 N m^-1` and is stretched by 1.0 cm. If a wave pulse is produced on the string near the wall, how much time will it take to reach the spring ?

Answer

0.05 s

Explanation

Tension in string is
`T = kx = 160 xx 0.01 = 1.6N`
Wave speed is `v = sqrt((T)/(mu)) = sqrt((Tl)/(m))`
= `sqrt((1.6 xx 0.4 )/(0.01) ` = 8 m/s
time taken by pulse `t = (l)/(v) = (0.4)/(8) = 0.05 s.`