How Far Does a Car Slide on Wet Concrete Before Stopping?

[astru025]

Ap physics friction force please help!

Homework Statement

A 1000kg car traveling at a speed of 40m/s skids to a halt on wet concrete where the friction force is 6000N. How far does the car slide before coming to a stop?

Homework Equations

F=mv^2 / r
1000 kg x (40 m/s^2) / r = 6000 N
I got 266.7

The Attempt at a Solution

I came up with a positive number and it should be a negative number... What am I doing wrong?!

 

[Simon Bridge]

Why would you expect a negative number?
(And don't forget units.)

F=mv^2/r is for centripetal force isn't it? Is the car going in a circle?

 

[lep11]

Homework Statement

I came up with a positive number and it should be a negative number... What am I doing wrong?!

Well..it always depends on which direction you choose to be positive and which negative.
However, the equation you used wasn't correct. Think it in terms of work and energy.