How far does the car travel before stopping?

[collegegirl]

Homework Statement

Car: mass = 200g
Moving at 30 m/s
Braking force of 10000N.
How far does the car travel before stopping?

Homework Equations

W=m x N
w = F (delta x)

The Attempt at a Solution

I found work, (2000)(10000) = 20,000,000
Then rearranged the second equation to get delta x, and got 2000 as my answer. The answer is 90m and I'm not getting it. Any suggestions?

 

[asleight]

Homework Statement

Car: mass = 200g
Moving at 30 m/s
Braking force of 10000N.
How far does the car travel before stopping?

You can go one of two routes:

(1) $$\vec{F}=m\vec{a}$$ and $$\vec{v}_f^2=\vec{v}_i^2+2\vec{a}\Delta x$$, or

(2) $$\Delta E_k=\vec{W}$$, where $$\vec{W}=\vec{F}\Delta x$$.