College Physics
posted by Suzy .
The driver of a 1600 kg car, initially traveling at 10.6 m/s, applies the brakes, bringing the car to rest in a distance of 23.0 m.
(a) Find the net work done on the car.
(b) Find the magnitude and direction of the force that does this work. (Assume this force is constant.)

a) net work equals the change in KE.
or, Vf^2=Vi^2+2ad solve for a
then work= force*distance= mass*a*distance.
b) force= ma 
I worked out the first equation for part a and found the acceleration to be 0.2304. When doing the second equation, I found work to be 8478.72 J. Can work be negative? I feel like I haven't worked this out correctly.

I feel like the acceleration isn't correct.