How can i scroll gameobject using touch?

i want to rotate my object as i drag my finger, and spin it when i swipe and release. I want to scroll the game object similar to how you would scroll ui

 

Plenty of tutorials out there on Youtube, or you're welcome to take a look at my project folder here.

 

how can i make the scrolling inertia based, so that it keeps spinning for a while after i release the mouse or touch

 

I would track and record how fast it is rotating when the player has their finger down and is spinning it, perhaps averaged over a few frames.

Then when their finger comes off, have code that continues to inject motion equivalent to the previously-taken reading, and slowly wind that down to zero over the next X amount of time.