Question

A car is traveling with a veracity of 80km/hr slowed down to 44km/hr in 15 sec.the retardation is..??

Answer 1

v= 44km/h = 44* 5/18 =12.22...m/s
u= 80km/h= 80*5/18 = 22.222...m/s
t= 15 sec

a= v-u/t
= 12.222..-22.222../15
=-10/15
=0.6666.....(reccurring) m/s square

Answer 2

Initial velocity, u = 80 kmph = 80*5/18 m/s
Final velocity, v = 44 kmph = 44* 5/18 m/s
Time, t = 15 s = 
v= u + at
44* 5/18 = 80*5/18 + a* 0.25
a= 40 metre/ second square