# I Difference between translation and uniform motion

1. May 17, 2017

### Pushoam

2. May 17, 2017

### Zach S

yes by the looks of it the basis of uniform motion was from his translational veiw of space and time and how a ball will go through uniform acceleration on a ramp.

3. May 17, 2017

### Pushoam

Then, why does wikipedia treat translation and uniform motion differently?

4. May 17, 2017

### Zach S

translation is needed to describe uniform motion a movement through space and time not exactly the same but is needed to describe uniform motion

5. May 18, 2017

### Pushoam

o.k.
Thank you.

6. May 18, 2017

### Ibix

In the notation they are using, translation is the relationship between the coordinates used by me and the guy sat next to me. Uniform motion is the relationship between the coordinates used by me and someone sitting in a passing train.

In the first case, the difference between the coordinates is just a constant offset. If I say something is at $x=-1$ (i.e. 1m to my left), the other guy says it's at $x'=-2$ (i.e. 2m to his left). That is true for all times.

In the second case, the difference between the coordinates is a time-varying offset. If the train is moving at speed v past me, I say that the passenger is at $x=vt$ at time t. However the passenger regards herself as at rest at $x''=0$, and me as moving at -v, so I am at $x''=-vt$.

That's the difference. The first one leads to "the laws of physics are the same at all places" and the second to "the laws of physics are the same at all speeds".