question_answer

Mountain roads rarely go straight up the slope, but wind up gradually. Why?

Answer:

                If roads were to go straight up, the slope \[(\text{ }\!\!\theta\!\!\text{ })\] would have been large, the frictional force \[(\mu \,\text{mg cos }\!\!\theta\!\!\text{ })\] would be small. The wheels of the vehicle would slip. Also, for going up a large slope, a greater power shall be required.