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I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled with what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, M1 and M2, in empty space that each have a mass of 1 kilogram. M1 flies toward M2 in a perfectly straight line with a velocity of 1 meters per second. M1 sticks to M2, creating M3, and the new 2 kilogram rectangular block moves with a velocity of 1/2 meters per second. In the collision, 1/4 J of energy was lost.

What happened to that energy, given that no sound or heat was emitted? Does it requires a certain amount of energy to form a single 2 kilogram object out of two 1 kilogram objects?

I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled with what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, M1 and M2, in empty space that each have a mass of 1 kilogram. M1 flies toward M2 in a perfectly straight line with a velocity of 1 meters per second. M1 sticks to M2, creating M3, and the new 2 kilogram rectangular block moves with a velocity of 1/2 meters per second. In the collision, 1/4 J of energy was lost.

What happened to that energy, given that no sound or heat was emitted? Does it requires a certain amount of energy to form a single 2 kilogram object out of two 1 kilogram objects?

EDIT:

I was able to figure things out thanks in great part to the posts below. In case this bothers someone else in the future, the way that I think about it is, it requires energy to slow down M1 and speed up M2 to the same velocity (you can imagine M3 as two separate particles). Fundamentally, the energy is lost in that speeding up/slowing down process in a world without friction, heat, etc.

I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled about what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, $M_1$ and $M_2$, in empty space that each have a mass of $1$ kilogram. $M_1$ flies toward $M_2$ in a perfectly straight line with a velocity of $1$ meter per second. $M_1$ sticks to $M_2$, creating $M_3$, and the new $2$ kilogram rectangular block moves with a velocity of $1/2$ meters per second.

  In the collision, $1/4\,\mbox{J}$ of energy was lost. What happened to that energy? Does it require a certain amount of energy to form a single $2$ kilogram object out of two $1$ kilogram objects?

I would appreciate any insights. If you have any material that I could read or watch that you think addresses some flaw in my thinking, please let me know.

I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled with what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, M1 and M2, in empty space that each have a mass of 1 kilogram. M1 flies toward M2 in a perfectly straight line with a velocity of 1 meters per second. M1 sticks to M2, creating M3, and the new 2 kilogram rectangular block moves with a velocity of 1/2 meters per second. In the collision, 1/4 J of energy was lost. 

What happened to that energy, given that no sound or heat was emitted? Does it requires a certain amount of energy to form a single 2 kilogram object out of two 1 kilogram objects?

I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled with what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, M1 and M2, in empty space that each have a mass of 1 kilogram. M1 flies toward M2 in a perfectly straight line with a velocity of 1 meters per second. M1 sticks to M2, creating M3, and the new 2 kilogram rectangular block moves with a velocity of 1/2 meters per second. In the collision, 1/4 J of energy was lost. What happened to that energy? Does it requires a certain amount of energy to form a single 2 kilogram object out of two 1 kilogram objects, given that no sound or heat was emitted?

I would appreciate any insights. If you have any material that I could read or watch that you think addresses some flaw in my thinking, please let me know.

I’m going over a chapter on linear momentum in my physics course right now and am somewhat puzzled about what happens with some of the kinetic energy that is lost in a perfectly inelastic collision.

Imagine a world without sound, heat, or any non-mechanical forms of energy. Now imagine that there are two perfectly square blocks, $M_1$ and $M_2$, in empty space that each have a mass of $1$ kilogram. $M_1$ flies toward $M_2$ in a perfectly straight line with a velocity of $1$ meter per second. $M_1$ sticks to $M_2$, creating $M_3$, and the new $2$ kilogram rectangular block moves with a velocity of $1/2$ meters per second. 

In the collision, $1/4\,\mbox{J}$ of energy was lost. What happened to that energy? Does it require a certain amount of energy to form a single $2$ kilogram object out of two $1$ kilogram objects?

I would appreciate any insights. If you have any material that I could read or watch that you think addresses some flaw in my thinking, please let me know.