# Translational energy vs. kinetic energy

1. Jul 14, 2007

### physgirl

1. The problem statement, all variables and given/known data
Is translational energy the same thing as kinetic energy?

3. The attempt at a solution
In a sense, I feel like it is, since they both deal with energy of motion, but then again, isn't kinetic energy the sum of translational, rotational, AND vibrational motion?

2. Jul 14, 2007

### Andrew Mason

Correct. Translational energy is only one aspect of a body's kinetic energy. A three dimensional body has the ability to rotate about its centre of mass. Rotational energy is independent of translational motion of the center of mass. If the body is not rigid, there is additional energy of compression/expansion (vibration).

AM

3. Jul 14, 2007

### physgirl

So then given mass and velocity of a particle, how would you find the translational energy of a particle...?

4. Jul 14, 2007

### olgranpappy

it's not actually called "translational energy" it's called "translational kinetic energy." Use the usual formula for kinetic energy $$m v^2/2$$. We have introduced the new adjective "translational" because we will soon be studying extended bodies (or, apparently, you will) which have in addition to "translational kinetic energy" also "rotational kinetic energy."