One dimensional motion problem, overcoming head start

[creechur]

I know this problem has been posted before, but I think my answer is correct and I want to know why it was considered wrong!

Homework Statement

Cars A and B are racing each other along the same straight road in the following manner: Car A has a head start and is a distance D_a beyond the starting line at t=0. The starting line is at x=0. Car A travels at a constant speed v_a. Car B starts at the starting line but has a better engine than Car A, and thus Car B travels at a constant speed v_b, which is greater than v_a.

Homework Equations

x_b=x_a
when b catches up to a

The Attempt at a Solution

I just set the two equal to one another:

v_b(t) = D_a + V_a (t)

solving for t I arrived at

t = D_a \ (v_b - v_a)

and was quickly told that the answer didn't depend on v_a and v_b...If that's true then I have no idea where to proceed and would appreciate any guidance on where to start.

 

[ideasrule]

solving for t I arrived at

t = D_a \ (v_b - v_a)

and was quickly told that the answer didn't depend on v_a and v_b...If that's true then I have no idea where to proceed and would appreciate any guidance on where to start.

What's the actual question? If it asks you for the time it takes B to catch up to A, then your work is right.

 

[creechur]

What's the actual question? If it asks you for the time it takes B to catch up to A, then your work is right.

that is the actual question, my inability to distinguish letters was the problem, thanks for the help

wow, I feel dumb. My homework is entered electronically online, and I was actually putting the wrong variable for the velocity of the two cars. I was entering the greek letter nu because I thought that was what the problem was using...turns out it was lowercase v. Still, glad I found this site and will definitely be using this in the future, but this thread can be closed.