Question

A car accelerates at a rate of 5m/s2 for a period of 4.2 seconds and then moves at a constant speed for 8 seconds more. How far did it travel?

Answer 1

t = 4.2
T = 8
a = 5
I guess it started from a dead stop.

x = (1/2) a t^2 during acceleration

Vi = speed at end of acceleration = a t

X = Vi T during constant speed so

distance = (1/2) a t^2 + Vi T

Answer 2

212