Answer:
 v =  7.67 m/s  for L= 1m
Explanation:
Let's use the conservation of mechanical energy, at the highest point and the lowest point
Initial. Vertical ruler
    Em₀ = mg h
Final. Just before touching the floor
    [tex]Em_{f}[/tex] = K = ½ I w²
   Em₀ = [tex]Em_{f}[/tex]
   m g h = ½ I w²
The moment of inertia of a ruler that turns on one end is
   I = 1/3 m L²
Let's replace
   m g h = ½ (1/3 m L²) w²2
   g h = 1/6 L² w²
They ask for the speed of the end so the height h is equal to the length of the ruler
   g L = 1/6 L² w²
The linear and angular variables are related
   v = w r
   w = v / r
In this case the point of interest a in strangers r = L
   g L = 1/6 L² v² / L²
   v = √ 6 g L
Let's calculate
Assume that the length of the meter is L = 1 m
  v = √ (6 9.8 1)
  v =  7.67 m/s