It's simple physics.
The data density is equal per sector throughout the platter.
In the case of the Samsung F3, its rotational spindle speed is 7200RPM. Regardless if this is the inner or outer region of the platter, the platter rotates 7200 times every minute.
The read/write head does not rotate. However, the velocity of the platter in relation to the read/write head increases, the further out into the platter you go.
You can easy check this yourself.
Take an old DVD media.
Using a pen, mark dots with the pen approx 1cm apart right around the inner edge of the recording area, and lets call each dot a sector. you'll end up something like 14 dots.
Now do the same at the outer edge of the disc, you'll end up with around 45 dots, each one representing a sector.
Now draw a straight line from the inner edge to the outer edge.
Now rotate the disc slowly for one complete rotation.
For one rotation, the inner edge will read 14 sectors, while the outer edge will have read 45 sectors.
So it's simple physics, the outer edge of the platter has a higher velocity, so data transfer at the outer edge is faster than at the inner edge.
BTW: Burst rate is only a measurement of the interface, not what the drive is physically able to read or write at.