Question

please answer this numerical tommarow my exam step by explanation​

Answer 1

when acceleration increases that is when rate of change of velocity increases it is called postive acceleration

when acceleration decreases that is when rate of change of velocity decreases it is called deacceleration or negative acceleration

we have formula

v=u+at

given

v=72

u=90

t=5

at=v-u

5a=72-90

5a=  -18

a=   -18/5

a=  -3.6 m/s^2

hence retardation is 3.6 m/s^2

hope this helps