Dropping it on a hard surface.
The initial height of the first body is given by:

where
g is the gravitational acceleration
t is the time it takes for the body to reach the ground
Substituting t=1 s, we find

The second body takes takes t=2 s to reach the ground, so it was located at an initial height of

The second body started its fall 1 second before the first body, therefore when the second body started its fall, the first body was located at its initial height, i.e. at 4.9 m from the ground.
The molecular geometry of both F2 and HF is linear.There are only two atoms which are covalently bonded and thus, the bonding scheme with the atoms looks like this;
F --- F
H---F
So, both are linear.