A Slinky $($spring$)$ having an unstretched length close to zero behaves like a string as far as the speed of transverse waves propagating along it$.($i$.$e$.v^2=\frac{F}{\frac{m}{L}}).$ A Slinky of mass $m=0\mathrm{.}05kg$ is stretched to a length of $L_1=6m.$ When a wave pulse is shaken into it$,$ the pulse takes $t_1=0\mathrm{.}8s$ to travel to the other end.

The Slinky is now stretched to a new length of $L_2=10\mathrm{.}2m.$ How long does it take a wave pulse to travel the new $10\mathrm{.}2$ m length of the Slinky?