How Does a Car Overtake a Truck After a Traffic Light Turns Green?

[CHARG3RS]

Homework Statement

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 traveling when it overtakes the truck?

Homework Equations

a=Vf-Vi/DeltaT
deltad=1/2(Vi+Vf)deltat
deltad=Vi x deltat + 1/2a(deltat)^2
deltad=Vf x deltat - 1/2a(deltat)^2
Vf^2=Vi^2+2a deltad

The Attempt at a Solution

car
Vi = 0 m/s
a = 6.0 m/s^2
Delta d = ?

truck
Vi = 21 m/s
Vf = 21 m/s
a = 0 m/s^2

I can only see these variables in the question, and I don't know what formula to use. Could someone point me in a direction please? I'm really stressing over this, I've tried multiple times.

 

[collinsmark]

Hello CHARG3RS,

Welcome to Physics Forums!

I can only see these variables in the question, and I don't know what formula to use. Could someone point me in a direction please? I'm really stressing over this, I've tried multiple times.

Okay, you've tried multiple times. Show us your attempt and tell us where you are getting stuck, and maybe we can help.