1. The problem statement, all variables and given/known data "Before the collision, vehicle #1 was traveling east and vehicle #2 was traveling north. The driver of vehicle #1 states he was traveling 35 mph as he approached the intersection. He continues to state that vehicle #2 ran the stop sign, pulling out in front of him and causing him to crash. The driver of vehicle #2 states that he stopped at the stop sign before pulling out, and did not see vehicle #1 until the moment of impact. (From the stop sign, vehicle #2 would have traveled 30 feet to the point of impact. After the collision, both vehicles experience wheel lock due to crash damage and skidded over asphalt (μk = 0.72) followed by grass (μk = 0.35). Neither surface has any significant incline. Vehicle #1 skidded on 20 feet of asphalt and 30 feet of grass before coming to rest. The angle of departure for vehicle #1 was 45 degrees north of east. The weight of vehicle #1 including occupants was 4300 lbs. Vehicle #2 skidded on 25 feet of asphalt and 35 feet of grass before coming to rest. The angle of departure for vehicle #2 was 35 degrees north of east. The weight of vehicle #2 including occupants was 3150 lbs. An acceleration test concluded that a vehicle such as vehicle #2 would have a maximum acceleration of 2.0 m/s^2 at the time of the accident. ...What was the speed of each vehicle after the collision?" 2. Relevant equations (I'm all over the place, but...) KE = (1/2)(m)(v^2) W = Fd(cosθ) W = ΔKE F(friction) = (μk)(F(normal)) = (μk)(mg) KE1 + PE1 + W(external) = KE2 + PE2 J = FΔt = mΔv = Δp p = mv 3. The attempt at a solution Originally, I used the fact that the work of friction is equal to the change in kinetic energy, so: W(f) = ΔKE (μk)(mg)(d)(cosθ) = (1/2)(m)(v^2) √[2(μk)(g)(d)(cosθ)] = v But this doesn't account for the change in surfaces, from asphalt to grass. Also, I'm not even sure if it properly accounts for the two-dimensions of the collision. I'm aware that this is a 2D elastic collision problem, and understand how to split the x- and y-components of the velocity. However, I don't think I'm approaching this properly. Any help would be greatly appreciated. Thank you!