Lt. Henry first noted that the weather was clear and sunny at 69 F and the roadway was dry. Refer to the sketch below: Main Street, a thoroughfare, has a 45mile per hour speed limit. State Street also has a 45mile per hour limit, but has a stop sign on either side of the road. The mass of Car 1 was 2060 lbs and that of Car 2 was 5800 lbs. Investigation of the road showed that after impact, the two cars initially travelled in the same direction. It also demonstrated that Car1 showed no skid marks after the impact and that it had come to rest next to the house on the corner. Further examination of the road also verified that Car2 had skidded for 24feet before coming to a stop next to the utility pole (marked Dec#20 in the figure below). The impact areas of the cars made it clear to Lt. Henry that the collision had taken place at right angles between the front right bumper of Car2 and the front left bumper of Car1. The sketch below is on scale. At this time, Lt. Henry received information that the driver, who had become unconscious at the scene of the accident, had died at the hospital. By using a drag sled, Lt. Henry determined that the coefficient of friction between the tires of Car 2 and the road was 0.60. He could not use the drag sled to determine the coefficient of friction between the tires of Car 1 and the road as it had rolled over the roadway and grass.

Think about these questions 10. Did Lt. Henry need to find the coefficient of friction for Car 1? What procedure could he have used to find this information? 11. Using your outlined procedures, find the velocities of the two cars just prior to the impact. 12. Estimate the coefficient of friction between the rolling tires of Car 1 and the roadway and grass. Be sure to state any assumptions that you make and justify them. 13. During the collision, which car delivered the greater force of impact? Justify your reasoning using physics principles. 14. How did Lt. Henry determine the speeds of both cars just before they applied their brakes? What further information will he need?

Weather & Road Conditions: Clear Dry Asphalt, 69 deg. house house stop sign 22' POI-A B 7'g" unimproved shoulder Oref point C O Dec house #20 12'2" house D