An elastic string has a force constant k and mass m. the string hangs vertically, and a block of an unknown mass is attached to its bottom end. It is known that the mass of the blocks is much greater than that of the string. The hanging block stretches the string to twice its relaxed length. how long (t) would it t take for a low-amplitude transwerse pulse to travel the length of the string stretched by the hanging block ? m=1 kg, `k=1/2 N//m`.

Explanation

`T=Mg-kDeltat=kxxl`
`l(2l)/(v)=(2l)/sqrt((T)/(mu))=(2l)/sqrt((kl)/(m//2l))`
`=(2l)/sqrt(2kl^(2)//m)=sqrt((2m)/(k))=2` sec.