Question

Questions on Banked Circular Tracks with Friction.

1. A box rests on a horizontal board. One side of the board is raised until the box begins to slide. Find the coefficient of static friction between the box and the board from the final angle of the board, when the box just begins to slide.

Answer 1

2. A car is traveling on a circular track of radius 100m banked at 30° with coefficient of friction 4 with car tires. At a certain speed, centripetal force is due only to normal force, and friction force is zero. If the car is traveling slightly faster than this speed, then the friction force will point
A) up the incline B) down the incline C) to the center of the circular path

3. What is the maximum speed at which a car can maintain uniform circular motion without skidding on the track in the previous problem?

4. A car drives around a circular track of radius 80m. If the track is flat and has
coefficient of static friction 1.0 with the tires, then the maximum speed of the car is
28m/s. If instead the track was frictionless but banked or inclined at an angle, what
bank angle is necessary to allow uniform circular motion at 28m/s?

Answer 2

K I got 4 is 45