physics
posted by help .
At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.3 m/s2. At the same instant a truck, traveling with a constant speed of 9.4 m/s, overtakes and passes the automobile.
(a) How far beyond the traffic signal will the automobile overtake the truck?
m
(b) How fast will the car be traveling at that instant?
m/s

at some time t, the same time for both cars, they have went the same distance d.
You have two equations
Truck: d=vi*t
Car: d=1/2 a t^2
set the equal, solve for t, thensolve for d.