Let's take a couple of very common modelling assumptions, which you should definitely at this level take as standard:
Air resistance is negligible
Acceleration due to gravity is constant over small changes in height, relative to the size of the Earth
With these in mind, we just use Newton's Equations of Motion under constant acceleration. We want to solve for the displacement h, and the initial velocity is zero as 'dropped' implies from rest:
s = h
u = 0
v = ?
a = 9.81
t = 3.0
s = ut + 0.5at^2
= (0)(3.0) + (0.5)(9.81)(3.0^2) = 44m (2sf)
I hope this helps you :)
