An accident investigator estimates that a vehicle hit a bridge abutment at a speed of 15mile/hr, based on his assessment of damage. Leading up to the accident location, he observes skid marks of 150ft on the pavement (F=0.25) and 60ft on the grass shoulder (F=0.3). There is no grade. An estimation of the speed of the vehicle at the beginning of the skid marks is desired bro can u do this one