Compute the speed of 2 kg ball having kinetic energy of 4J

Given, mass of ball, m =2 kg
Kinetic energy of ball, KE = 4 J
KE = 1/2 m ${{v}^{2}}$
${{v}^{2}}$ = 2KE / m = 2 x 4 / 2 = 4
v =2 ${{ms}^{-1}}$