Answer
$T=1.8\times 10^4N$
Work Step by Step
We know that
$v_f^2-v_i^2=2aS$
This simplifies to:
$a=\frac{v_f^2-v_i^2}{2S}$
We plug in the known values to obtain:
$a=\frac{(0)^2-(12)^2}{2(42)}$
$a=-1.71\frac{m}{s ^2}$
Besides this force, there is also gravitational force so the total force $F$ is given as,
$F=ma+mg=m(a+g)$
We plugin the known values to obtain:
$F=1600(-1.71-9.81)$
$F=-18432N$
The tension has the same magnitude but in opposite direction:
$T=18432N$
$T=1.8\times 10^4N$
