6.At the end of the 7th second the brakes are applied and the car slows down at a constant rate till it comes to rest in 5s. What is the acceleration?

7.Draw the v vs.t graph
8.find the final displacement: a)by using the graph b)by algebraic calculations using relevant formulae

a= v-u/t

= 0-(-20)/5s
= 4m/s^2