A newly minted detective with a physics background investigates a crash where one car (A) hits a parked car (B). There's no obvious evidence that driver A applied the brakes before the collision. After the collision, the two cars stuck together and slid until they came to rest. The detective wants to figure out if A was speeding before the collision, so she takes the following steps: 1. Measure the length (d) of the skid marks to determine post-crash sliding distance. 2. Determine the coefficient of kinetic friction () between the car tires and the ground. 3. Look up the masses of the two cars (mA, mB ). 4. Find the amount of work done by friction as the cars slide, using the definition of work:~Favg ~x = (mA + mB )gd 5. Use conservation of energy to determine the speed of the cars just after the crash, vf , via the equation: 1 2(mA + mB )v2f = (mA + mB )gd 6. Use conservation of energy to determine the initial velocity of the first car, vA, via the equation: 1 2mAv2A = 1 2(mA + mB )v2f 7. Compare vA to the speed limit to see whether the car was speeding.