Question

if a car can accelerate at 6m/s2, how fast can it accelerate if it is towin an identical car behind it?

Answer 1

A truck is stopped for a red light at Ridge Road on Higgins line. At the instant the light turns green, the truck pulls away with a constant acceleration of 3.3 m/s2. A cyclist approaching the truck with a constant velocity of 12.0 m/s is 8.60 m behind the truck when the light turns green.
(1) What is the elapsed time from the changing of the light to when the cyclist passes the truck?
(2)What is the elapsed time from the changing of the light to when the truck repasses the cyclist?


i know how to do number 1. but i'm stuck on number two. i have the answer (6.38s) but i have no idea how to get that answer. any help would be greatly appreciated! thanks