4. A car skidded going into an intersection, struck a pedestrian, and continued until it hit a tree. Based on the damage to the front of the car, it is estimated that the car was doing 10 kph at...

Extracted text: 4. A car skidded going into an intersection, struck a pedestrian, and continued until it hit a tree. Based on the damage to the front of the car, it is estimated that the car was doing 10 kph at impact with the tree. The length of the skid marks was measured at 42 m. The road is on a downhill grade -5 percent. A test car skidded 15.5 m on the same section of rod when braked from a speed of 45 kph to a halt a.) What is the coefficient of friction between the tires and the pavement ? b.) What is the probable speed of the car involved in the accident when the brakes were applied ? c.) If the perception reaction time of the driver is 1.5 seconds, what could have been its minimum total stopping distance to avoid the crash ?