θ(t) is the angular rotation as a function of time
Δθ is the change in angle (angular displacement)
w is the angular velocity
α is the angular acceleration
t is time
If we assume constant angular acceleration, we have the following formulas. Note that the subscripts 1 and 2 denote "initial" and "final".
These formulas apply to every particle in a rigid body that is experiencing rotation, such as the disk shown in the first figure. In other words, all the particles experience the same angular displacement, angular velocity, and angular acceleration regardless of their position relative to the center of rotation.