How Much Work is Required to Stop a Car Just Before a Collapsed Bridge?

[kza62]

Homework Statement

A car and driver weighing 5490 N passes a sign stating “Bridge Out 29.3 m Ahead.”
She slams on the brakes, and the car decelerates at a constant rate of 10.9 m/s2.
The acceleration of gravity is 9.8 m/s2 .
What is the magnitude of the work done stopping the car if the car just stops in time to avoid diving into the water?
Answer in units of J.

Homework Equations

KE = 1/2mv^2
Ff = u * FN
FN = mg
F = ma

The Attempt at a Solution

Given:
a = -10.9
Fg = 9.8

need help in setting this problem up... I've never seen something weigh in N before is that important or relevant in any way? would I plug that into F = ma to find mass?
help please!

 

[rock.freak667]

If the weight is 5490 N, can you find the mass of the person+car ?

If the deceleration is -10.9 m/s² , can you get the force of friction acting on the car?

If you have the frictional force, can you find the work done by this force given the distance?