Ideal Brain

The brain of a physics student should ideally be filled with lots of physics knowledge.

The force of a spring is kx, where k is the spring constant and x is the distance from the equilibrium point. There are free body diagrams of the forces acting on a block, whether it's on an incline, hanging from a pulley, or hanging from a spring. F=ma is very important, since it's Newton's 2nd law and can be applied in multiple units multiple ways. Students should be able to draw a circuit. There are so many important things to learn in physics, from energy and momentum to circuits and magnetism.