Acar of mass m1 stopped at a traffic light is rear-ended by a car with mass m2. the cars become entangled. the second car was moving at a velocity of v2 before the collision. what is the kinetic energy of the system after the collision?

By momentum conservation we can find the final velocity of two cars

now we know that they combined together after collision and first car is at rest initially

now the kinetic energy of two combined cars is

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )