An airplane maintains a speed of 630 km/h relative to the air it is flying during as it makes a trip to a city 750 km away to the north. (a) What time interval is needed for the trip if the plane flies through a headwind blowing at 35.0 degrees km/h toward the south? (b) What time interval is required if there is a tailwind with the same speed? (c) What time interval is needed if there is a crosswind blowing 35.0 km/h to the east relative to the ground?