Question

Question #872c3

Answer 1

`a= 100m/s^2` deceleration
F= 100.000 N

Explanation:

using the two movement equations you have:
`S= v°t -1/2 at^2` and
`v= v°-at`
where v= 0 m/s (the car is stopped) V°= 20m/s . and acceleration has the opposite verse of velocity
From the second equation you have
`t= (V°)/a` that putting in the first equatin gives:`S= (V°^2)/a -1/2 (V°^2)/a =1/2 (V°^2)/a`
i.e
`2m =1/2 (20m/s)^2/a`
then
`a= 100m/s^2`
from the second dinamic equation: F= ma we have `F= 1000 kg xx 100m/s^2= 100.000 N`