Question

please answer this questions

Answer 1

Weight of car =1000kg
Initial velocity=u=30m/s
since car stops
final velocity = v=0m/s
distance taken to stop =50m
We know that from Newton's law of motion
${v}^{2} = {u}^{2} + 2as$
where "s" is distance
s=50 m
${0}^{2} = {30}^{2} + 2a \times 50 \\ 900 + 100a = 0 \\ 100a = - 900 \\ a = - \frac{900}{100} \\ a - 9m {s}^{ - 2}$
since it is retardation.
$a = 9m {s}^{ - 2}$
we know that
F=ma
F=1000×9
F=9000N
We know that

work done= force × displacement
work done=9000×50
work done=450000 joule