1. The problem statement, all variables and given/known data A motorist suddenly notices a stalled car and slams on the brakes, negatively accelerating at 6.1m/s2 . Unfortunately this isn't enough, and a collision ensues. From the damage sustained, police estimate that the car was going 22km/h at the time of the collision. They also measure skid marks 35m long. Aow fast was the motorist going when the brakes were first applied? B: How much time elapsed from the initial braking to the collision? 2. Relevant equations 2 a (x - xo)= v2 - vo2 v(average)=d/t 3. The attempt at a solution A: 2(6.1m/s^2)(35-0m)=(55/9m/s)^2-vo^2 vo^2=19.7m/s B: 19.7m/s=35/t t=1.78sec I may just be totally off, but I feel like I understood the problem. Masteringphysics doesn't agree. Thanks again haha.