For the position, we can use the equation below for our calculations:
H = h + v₀²/2g
where
H is the total height from the base of the cliff to the highest point of the rock on air
h is the height of the cliff
v₀ is the initial height
g is equal to 9.81 m/s²
H = h + 13²/2(9.81)
H = h + 8.61 m
Because the height of the cliff is not known, the answer would just be h +8.61 m.
For the velocity, we use the equation: v = √2gH. Substituting the answer for H, the velocity is
v = √2(9.81)(h+8.61)
v = 4.43√(h+8.61)