Calculating Frictional Work on a Moving Car

[preluderacer]

Homework Statement

How much work must be done by frictional forces in slowing a 1000kg car from 29.8m/s to rest?

The Attempt at a Solution

Im not quite sure how to go about this problem. I know the frictional force is 9800N times the coefficient of friction. And I know the car isn't accelerating prior to slowing down. I am not quite sure how to fit this all together. A little guidance would be greatly appreciated =)

 

[Delphi51]

Working with the coefficient of friction is the wrong approach for this. Use an energy approach. How much energy must be converted to heat?

 

[preluderacer]

oh I get it I need to use the kinetic energy equation from 28.9 to 0?

 

[preluderacer]

I plugged it into the equation 1/2(m)v^2 and solved from 0 to 28.9. My answer was 444020 J. Does this seem like the right method?

 

[Delphi51]

Looks good!