How can kinetic energy decrease in an inelastic collision, but momentum stay the same?

Question

I have been doing research and the explanations don’t make sense. Kinetic energy is based off of velocity, and so is momentum. If the kinetic energy decreases, the momentum would also have to decrease, because the objects in the collision have less energy and therefore move at slower rate, and therefore have less momentum. It seems like momentum and energy are one, but but in reality it isn’t? And here’s my thought experiment:

Two objects collide and lock together. They maintain their original momentum, but are now locked together as one. According to what I am currently learning, they have lost kinetic energy, but they have maintained their total momentum. Now, the locked objects hit an equal copy of themselves in front of them, except the copies are unlocked. Due to conservation of momentum, the locked object stops, and the copies are now at the same point the two objects were at the start of the experiment, before they collided. How can energy be lost, and then gained? Where did they go? If someone could simply explain what I’m missing, that would be very helpful as I have a test in 12 hours. Thanks!!

In: Physics

Answer 1

You thought experiment is horribly explained because I’ve read it 4 times and can’t follow it. You’re leaving out way too much information I think like the actual mass and velocity of the objects.

Because that’s another thing, kinetic energy and momentum also both depend on the mass of the objects too.

But you’re describing, no energy has been lost or gained at all, it’s all just kinetic energy in the moving of the objects, all that is changing is what objects currently have the energy.

For example, say you have 4 bowling balls of the same mass, if you roll ball A into ball B, the kinetic energy is just getting transferred form ball A to ball B. Then if ball B hits ball C and D at the same time, the kinetic energy is getting transferred for balls C and D and just getting split between C and D.

So even tho balls A and B aren’t moving anymore, and balls C and D are moving slowly, no kinetic energy has been gained or lost.