Step-by-step explanation:
Given
initial velocity(v_0)=1.72 m/s

using

Where v=final velocity (Here v=0)
u=initial velocity(1.72 m/s)
a=acceleration

s=distance traveled

s=0.214 m
(b)time taken to travel 0.214 m
v=u+at


t=0.249 s
(c)Speed of the block at bottom

Here u=0 as it started coming downward

v=1.72 m/s