1. 
Two toy cars are on the headon collision course. The mass and speed of the cars before the collision are m_{1}= 2.0 kg, m_{2}= 5.0 kg, s_{1}= 5.0 m/s to the right, and s_{2} = 10.0 m/s to the left, respectively. After partially inelastic collision the first car changes direction and is moving to the left with the speed of 10.0 m/s. What is the final velocity of the second car after collision?
