A uniform rope of mass $6 \mathrm{kg}$ and length $6 \mathrm{m}$ hangs vertically from a rigid support. A block of mass $2 \mathrm{kg}$ is attached to the free end of the rope. A transverse pulse of wavelength $0.075 \mathrm{m}$ is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is $K \mathrm{cm}$ where $K$ is