Two cars each travel at a constant speed around separate curved sections of roadway…
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
Two cars each travel at a constant speed around separate curved sections of roadway having the same radius.
• Car A follows a flat, unbanked curve where the interaction between the tires and the road is characterized by static friction.
• Car B follows a curve that is smoothly banked at an angle θ above the horizontal but is engineered so that the surface is effectively frictionless.
Assume both cars have identical masses and air resistance is negligible.
(a) Draw and label a free-body diagram for each car while it is in the turn.
(b) For each car, identify which force or combination of forces provides the net horizontal force that keeps the car moving in its circular path.
(c) Using your free-body diagrams and appropriate reasoning, explain why Car B can negotiate the same curve at a particular design speed without relying on friction, whereas Car A requires sufficient static friction to avoid sliding.
(d) Suppose the coefficient of static friction between Car A’s tires and the pavement is suddenly reduced (for example, by rain). Qualitatively discuss how the maximum safe speed for Car A changes and whether the speed of Car B is affected under the same conditions.