PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
During a braking test on a dry road, a car of mass 1200kg moving at 20m s−1 comes to rest in a straight line in 25m after the wheels lock and start sliding on the road surface.
(i) Assuming the retardation is uniform, calculate its magnitude.
(ii) Hence determine the coefficient of kinetic friction between the tyres and the road.
(iii) Using the same surface conditions, estimate the minimum stopping distance of the car if its initial speed is 30m s−1 and the wheels again lock immediately.