a. What is the maximum speed at which a car can travel over a hump-backed bridge whose radius of curvature is 18 m?
b. A railway wagon has a mass of 12 tonnes and the height of its centre of gravity is 1.5 m above the rails. The track width is 1.37 m and the wagon travelling at 70 km h 1 . What is minimum radius of level curve that the wagon can negotiate at this speed without overturning?