Getting one object to look at another object in Unity can be a very math intensive project. In 3D there is an easy way to do this by use the transform to look at another object with a simple call:
Quaternion.LookRotation(target.position – transform.position)
In 2D Unity doesn’t hold your hand and you have to figure it out yourself. Most look rotation guides for Unity focus on simply modifying the transform even when talking about moving a Ridgedbody with physics.
If you want to use physics on Ridgedbody to add torque to turn toward another object then the unifycommunity wiki has a guide for 3D. With slight modifications we can get this same code working for Ridgedbody2D: