I am going to help you using physics......
Mechanical Energy = Potential Energy + Kinetic energy (or vice versa)
ME = PE + KE
PE = mgh ( m= mass; g = gravity constant which is 9.81; h = height)
= (1kg)(9.81)(1m)
PE = 9.81
KE = 1/2mv^2 (m = mass)(v = velocity)
= 1/2(1 kg)(2 m/s^2)
= (1/2)(4)
KE = 2
ME = KE + PE
ME = 9.81 + 2
ME = 11.81
hope this helps :)