Final answer:
To determine the velocity of a 1200 kg car after an elastic collision with an 1800 kg car at rest, both conservation of momentum and kinetic energy must be considered. However, without the final velocity of the 1800 kg car or an additional condition, the exact velocity of the 1200 kg car post-collision cannot be solved.
Step-by-step explanation:
The question asks about the velocity of a 1200 kg car after an elastic collision with an 1800 kg car at rest. In an elastic collision, both momentum and kinetic energy are conserved. To find the velocity of the 1200 kg car after the collision, we can use the conservation of momentum which states that the total momentum before the collision is equal to the total momentum after the collision.
Let v1' be the velocity of the 1200 kg after the collision, and v2' be the velocity of the 1800 kg car after the collision. The initial momentum of the system is momentum of the moving car which is (1200 kg)*(5.0 m/s) = 6000 kg*m/s east. Since the other car is at rest, its initial momentum is 0 kg*m/s.
After the collision, the total momentum is (1200 kg)*v1' + (1800 kg)*v2'. Setting the total momentum before the collision equal to the total momentum after the collision gives us:
6000 kg*m/s east = (1200 kg)*v1' + (1800 kg)*v2'
Using the conservation of kinetic energy, we can set up a second equation because the kinetic energy must also be the same before and after the collision. However, to provide a specific answer to the student's question, we would need to know either the final velocity of the 1800 kg car or another condition that allows us to solve the system of equations.
Without additional information, we cannot solve for the exact velocity of the 1200 kg car after the collision.