A car slows from 22 m/s to 3 m/s with a constant acceleration of -2.1m/s2. How long does it require to do this

Question

How do u solve this problem

Answer 1

All you need to know is this: v=v0+at; v0=22, a=-2.1; v=3m/s; t=?
To solve for time:
v=v0+at
v-v0=at
(v-v0)/a=t

t=(3-22)/-2.1=41s