Question

complete the speed of 2kg was having kinetic energy of 4J.

Answer 1

m=2kg .K=4J
$k = \frac{1}{2} m {v }^{2} \\ 4 = \frac{1}{2} \times 2 \times {v}^{2} \\ \frac{4 \times 2}{2} = {v}^{2} \\ {v}^{2} = 4 \\v = 2$