Note that i didn't double check the calculation but the method should be right
Use the kinematics equations.
Taking downward as negative, a = -9.81 ms-2 (gravitational acceleration)
u (initial velocity) = 15
v (final velocity) = 0 (at the top where it turns direction)
Applying the formula
v = u + at
0 = 15 + -9.81t
t = 1.5290
Applying the next formula
s = ut + 1/2 at^2
s (displacement) = 15 (1.5290) + 1/2 (-9.81) (1.5290 ^ 2)
s = 11.468 m
s = ut + 1/2 at^2
0.072 x 1000 = 7u + 1/2 (2) (7^2)
u = 1.4694 ms-1
v = u + at
0 = 50 * 1000 / 3600 + (-2)(t)
t = 6.9444 s
EDIT: oops forgot the 2nd part:
v^2 = u^2 + 2as
0 = (50 * 1000 / 3600)^2 + 2(-2) s
s = 48.225 m < 50m
The damsel will be 1.775 m from death
Just for future references (when you learn about momentum etc), these kinematics equations are only applicable when the acceleration is constant.