A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 20.0 min at 70.0 km/h, 6.0 min at 85.0 km/h, and 60.0 min at 50.0 km/h and spends 40.0 min eating lunch and buying gas. (a) Determine the average speed for the trip. km/h (b) Determine the distance between the initial and final cities along the route. km

A car making a 110.0 mi journey travels at 51.5 mi/hr for the first 38.1 mi. At what speed must it travel during the rest of the journey so that the average speed for the entire trip is 68.5 mi/hr? 83.0 mi/hr

A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 60.0 min at 95.0 km/h, 14.0 min at 100.0 km/h, and 60.0 min at 50.0km/h and spends 25.0 min eating lunch and buying gas. (a) Determine the average speed for the trip. (b) Determine the distance between the initial and final cities along the route.

Usually, Tony travels to Bunbury from Perth city in 2.50 hours. One day he increases his average speed by 12.0 km/h and takes 22.5 minutes less time to reach Bunbury. (a) What was his usual average speed? What was the distance travelled? (b) On the way he stopped at a rail crossing (6.00 m wide) and a train (total length 144m) decelerating at -0.585 ms2 just entered the crossing with a velocity of 13.7 m s¹. Sketch a diagram and find the minimum time for the last carriage of the train to clear the crossing.