1. The problem statement, all variables and given/known data With brakes fully applied, a 1670 kg car decelerates from a speed of 78.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car? 2. Relevant equations W=f*s, KE= .5(m)(v^2) 3. The attempt at a solution I am not sure if for the first answer how to start the problem, I have the mass, but I do not know the acceleration to solve for F...how can I go about solving this problem? Also for the second question I thought I would just have to use the equation for KE to solve, but it doesnt seem to be working...any suggestions?