Adriver traveling at 100 km/h notices the speed limit changes to 50 km/h to enter town. the driver takes 0.9 s to slow down to 50 km/h with constant acceleration. we want to know how many meters the driver travels while slowing down.

18.72 m

Explanation:

Given initial speed of the vehicle(u) is 100 km/hr.=100*(5/18)m/sec=27.77m/sec

The final speed of the vehicle (v) is 50 km/h.=50*(5/18)m/sec=13.88m/sec

time taken(t)=0.9s

we know that v=u+at

13.88=27.77+a(0.9)

a= - 15.43m/

Also we know that

s=18.72m

Therefore the distance travelled is 18.72 m

they should be similar or the same

if they have a finite resultant