Tween animation

Short for in-betweening. In a tween animation, the beginning
and ending points are defined, as well as a timeline, and a curve
that defines the timing and speed of the transition.
The framework calculates how to transition from the beginning point
to the end point.

The documents listed above, such as the
Animations tutorial, are not specifically
about tweening, but they use tweens in their examples.

Physics-based animation

In physics-based animation, motion is modeled to resemble real-world
behavior. When you toss a ball, for example, where and when it lands
depends on how fast it was tossed and how far it was from the ground.
Similarly, dropping a ball attached to a spring falls
(and bounces) differently than dropping a ball attached to a string.

Animate a widget using a physics simulation
A recipe in the animations section of the Flutter cookbook.