Two cars A and B slide on an icy road as they attempt to stop at a traffic light. The mass of A is 1100 kg and the mass of B is 1400 kg. The coefficient of kinetic friction between the locked wheels of both cars and the road is 0.130. Car A succeeds in corning to rest at the light, but car B cannot stop and rear-ends car A. After the collision, A comes to rest 8.20 m ahead of the impact point and B 6.10 m ahead: see Fig. Both drivers had their brakes locked throughout the incident. (a) From the distances each car moved after the collision, find the speed of each car immediately after impact. (b) Use conservation of momentum to find the speed at which car B struck car A. On what grounds can the use of momentum conservation be criticized here?

Hrishant Goswami , 9 Years ago

Grade 10