Answer
$Work$ $Done= -5.8\times10^{4}$ $J$
Work Step by Step
We know,
$W= F.d$
Here again, we need the values of distance and the force.
Since they are travelling with an initial velocity of $37m/s$ and in this, case with a retardation of $4m/s^{2}$, we get the distance $d$ by using
$v^{2}= v_{o}^{2}+2ad$
Plugging the known values we get:
$0^{2}=37^{2}+2(−4)d$
$\frac{−37^{2}}{−8}=d$
$d ≈1.7×10^{2}$ $m$
Now, we need to find the force.
We know,
$F= ma$
So plugging in the values of mass and acceleration, we get:
$F=85\times(-4)= -340$ $N$
Now putting the values of force and distance in the expression $W=F.d$
and solving we get:
$W= (-340)\times (1.7\times 10^{2})= -57800J$
$W= -5.78\times 10^{4}J\approx -5.8\times 10^{4}$ $J$
