Answer
$Work$ $Done = -5.8\times10^{4}$ $J$
Work Step by Step
We know that:
$W= F.d$
To find W, we need the values of distance and the force.
Since they are travelling with an initial velocity of $37m/s$ and with a retardation of $2m/s^{2}$, we get the distance $d$ by using
$v^{2}= v_{o}^{2}+2ad$
Plugging respective values in it, we get:
$0^{2}=37^{2}+2(−2)d$
$\frac{−37^{2}}{−4}=d$
$d ≈3.4×10^{2}$ $m$
Now, we need to find the force.
We know;
$F= ma$
So plugging in the values of mass and acceleration, we get:
$F=85\times(-2)= -170$ $N$
Now putting the values of force and distance in the expression $W=F.d$ and solving we get:
$W= (-170)\times 3.4\times 10^{2}= -57800J$
$W= -5.78\times 10^{4}J\approx -5.8\times 10^{4}$ $J$
