Hello!!!!

Hope you are doing great!!

Given weight of the stone = 2 kg

kinetic energy = 250J

we know that , kinetic energy = 1/2 mv^2

1/2mv^2 = 250 J

1/2 (2)v^2 = 250

v^2 = 250

In the problem ,, given ,, Kinetic energy = potential energy

1/2mv^2 = mgh

v^2 / 2 = gh

v^2 / 2g = h

h=250/2(9.8)

h=12.755m

Therefore, height = 12.755m

Hope it helps!!!