What Happens When Two Cars Collide and Stick Together?

[ConstableZiM]

Homework Statement

An 1800kg car traveling north at 35 km/hr collides with an 1100kg car traveling east at 45km/hr. The cars stick together and skid to a stop (a) what is the velocity (speed and direction) of the two cars immediately after the collision? (b) How much kinetic energy is lost during the collision? (c) if the collision occurs during a time of 600 ms, what is the average force between the cars?

Homework Equations

Practice exam problem, none given

The Attempt at a Solution

I get an answer of 7.7 m/s at 51.8 degrees for a, but when I plug that into the kinetic energy equation of K = 1/2(m)(v^2) (initial) - 1/2(m)(v^2)(final), I get a number of 84648 J, even though its supposedly elastic? As for C, I get a force of 14800 N.

Am I doing this correctly? Help would be appreciated

 

[ConstableZiM]

Nobody? ;,[

 

[panchoman]

isn't not elastic. Whenever objects stick together, it's usually not elastic.

what you need to do it calculate the ideal energy (had it been elastic), and then calculatue the actual energy of the system, and subtract the two to figure out how much energy was actually lost