How Do You Calculate Stopping Distance and Time with Kinetic Friction?

[cbrons]

Homework Statement

1. A car moving at 20 m/s brakes and slides to a stop. If the coefficient of kinetic friction between the pavement and the tires of the car is 0.1, how far does the car slide?

A. 50 m
B. 100 m
C. 200 m
D. 400 m

2. A car moving at 20 m/s brakes and slides to a stop. If the coefficient of kinetic friction between the pavement and the tires of the car is 0.1, how much time is needed for the car to come to a complete stop?

A. 1 s
B. 10 s
C. 20 s
D. 40 s

Homework Equations

U(k)mgcos0

The Attempt at a Solution

Well the answers for both are C, as the back of the book states. The problem is, I don't understand how you can figure out either the time or distance with the information given... can anyone shed some light?

 

[rock.freak667]

Use energy conservation for the first one, the work done by friction is the change in kinetic energy.