Energy Transfer in Collision of 200000N & 400000N Cars

[Tubs]

This question is making me go in circles, any tips?

A car weighing 200000 N traveling 3 m/s slams into a stationary car weighing 400000 N. The collision connects the two cars. How much energy is transferred from kinetic energy to other forms of energy in the collision?

 

[siddharth]

In this question, the energy of the system (ie ,the two cars) is not conserved. You have to find the KE of the cars before and after collision and the difference would give you the KE lost to other forms.
Can you find this difference? (Hint: Conservation of momentum)