From what height did the body fall if at the moment of impact on the ground its speed was 10 m / s?

We use the law of conservation of energy:
mV0 ^ 2/2 + mgh0 = mVk ^ 2/2 + mghk
Consider everything relative to the surface:
1) hk = 0, because the object eventually fell to the ground.
2) V0 = 0, since at the beginning the body was motionless
3) Reduce the mass on the left and right.
4) g = 9.8≈10
5) Vk = 10
Substitute;
10h0 = 10 ^ 2/2
10h0 = 100/2
10h0 = 50
h0 = 50/10 = 5 meters