In the top row labeled Before Collision, the left train car approaches the right car with a grey arrow pointing to the left car car. The left car has below it m subscript 1 = 600 kilograms v subscript 1 = 4 meters per second. The right car has below it m subscript 2 = 400 kilograms v subscript 2 = 0 meters per second. In the bottom row labeled After Collision, two train cars move away linked together with a grey arrow pointing toward the right of the car on the right. Consider a system to be one train car moving toward another train car at rest. When the train cars collide, the two cars stick together.

What is the total momentum of the system

the answer is 2,400 kg • m/s <3

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.