Answer
a). $118.61m$
b). time taken $=4.92s$
c). For Lois Lane, $v=48.22m/s$
For Man of Steel, $v=73.8m/s$
These speeds would be fatal for Lois Lane.
Work Step by Step
a). In time t , sum of distances covered by both is equal to 300m.
So, Distance by Lois Lane+Distance by Superman=300m.
Or, $(0.5\times 9.8t^{2})+(0.5\times15t^{2})=300$
$t=4.92s$
Thus, $h=0.5\times 9.8\times 4.92^{2}=118.61m$
b). time taken $=4.92s$
c). For Lois Lane, $v=u+gt=0+9.8\times 4.92=48.22m/s$
For Man of Steel, $v=0+15\times 4.92=73.8m/s$
Since their relative speed is $48.22+73.8=122m/s$, this would be fatal for Lois Lane.
