A uniform rope $2.5\ \text{m}$ long hangs freely from a hook in the ceiling, as shown in the figure. A small sideways pulse is made at its bottom end and travels up to the hook. Taking $g = 10\ \text{m/s}^2$, the time the pulse takes to reach the top is

Fig. 1: A uniform rope 2.5 m long hanging from a hook in the ceiling, with a small pulse at its bottom end travelling up.