2. A driver traveling at 65 mi/h rounds a curve on a level grade to see a truck overturned across the roadway at a distance of 350 ft. If the driver is able to decelerate at a rate of 10 ft/s, at what speed will the vehicle hit the truck? Plot the result for reaction times ranging from 0.5 sec to 5 sec in increments of 0.5 sec and comment on the results 3. A car hits a tree at an estimated speed of 25 mi/h on a 3% upgrade. If skid marks of 120 ft are observe on dry pavement (F = 0.35) followed by 250 ft (F=0.25) on a grass- stabilized shoulder, estimate the initial speed of the vehicle just before the pavement skid began? 4. Drivers must slow down from 50 mi/h to 35 mi/h to negotiate a severe curve on a rural highway. A warning sigh for the curve is clearly visible for a distance of 120 ft. How far in advance of the curve must the sign be located to ensure that vehicles have sufficient distance to decelerate safely? Use the standard reaction time and deceleration rate recommended by AASHTO for basic breaking maneuvers