A Cadillac of mass 2210 kg going east collides with a Geo of mass 1240 kg headed north on a level highway. The cars remain tangled and slide to rest after traveling 25 m in a straight line at an angle of 20° north of east. The coefficient of kinetic friction for the tires on the road is 0.2. How fast was the Cadillac traveling before the unfortunate collision?

Answer 1

From the sliding distance and the coefficient of friction, compute the velocity of the joined pair immediately following the collsion.

MV^2/2 = mu*M*g*X
V^2 = 2*mu*g*X = 98 m/s
V = 9.90 m/s

Next, use conservation of momentum to solve for the initial speed of the Cadillac.

All of the eastward final momentum is due to the Cadillac's initial momentum.

3350 kg*9.90 m/s*cos 20 = 2210*Vcad,o

Solve for Vcad,o

Answer 2

A Toyota of mass 1500 kg is driving at 15 m/s NOrth when it rear-ends a Cadillac of mass 2500 kg also moving North at 9 m/s. (The driver of the toyota was probably texting) After the collision, the Toyota bounces back at 2 m/s. What is the speed of the Cadillac after the collision?