MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Department of Physics
8.01
W13D1-9 Colliding Cars Solution
Two cars initially traveling at right angle to each other collide at an intersection. After
the collision, the cars stick together and travel a distance s , at an angle θ to car 1’s
original direction. Car 1 has mass m1 , and car 2 has mass m2 . The coefficient of
kinetic friction between the road and the rubber is µ k . The goal of this problem is to
find the speeds of the two cars immediately before the collision. You may assume
that the acceleration of gravity is g , and that the force of the collision causes the
wheels to lock, so that the rotation of the wheels can be ignored. What were the
speeds of the two cars immediately before the collision?