# Homework Help: An acceleration/distance/velocity question.

1. Oct 16, 2008

1. The problem statement, all variables and given/known data

As a traffic light turns green, a waiting car starts with a constant acceleration of 6.0 m/s^2. At the instant the car begins to accelerate, a truck with a constant velocity of 21 m/s passes in the next lane.

A)How far will the car travel before it overtakes the truck?

B)How fast will the car be travelling when it overtakes the truck?

2. Relevant equations

i have all of the following formulas:
vf = vi+at
d = (vf+vi)/2 x t
d = (vi)(t) + 1/2(a)(t)^2
vf^2 = vi^2 + 2(a)(d)

3. The attempt at a solution

i'm thinking i have to set a distance equation equal to the other one for A. i'm just not sure how to start the problem or anything. and for B, do i use what i'll get for distance and plug it into another equation?

2. Oct 16, 2008

### Redbelly98

Staff Emeritus
(a) Write two separate distance equations, one for the car and one for the truck. What can you say about these two distances when the car reaches the truck?