The law of conservation energy
PE₁ + KE₁ = PE₂ + KE₂
From rest ⇒ v₁ = 0 ⇒ KE₁ = 0
Input the value:
PE₁ = PE₂ + KE₂
[tex]\tt mgh_1=mgh_2+\dfrac{1}{2}mv_2^2\rightarrow divide\:m\\\\gh_1=gh_2+\dfrac{1}{2}v_2^2\\\\9.8(1.226-0.126)=\dfrac{1}{2}v_2^2\\\\v_2=4.64\:m/s[/tex]