Cornell University
Cornell University: Astronomy: Electromagnetism and Charge
This site from Cornell University provides a very short, very telling comparison of matter and charge. This is a good site to check out on the subject, with a chart diagram to help with further information.
University of Minnesota
University of Minnesota: Mechanics Problems: Force and Linear Kinematics Problem
This University of Minnesota site provides a series of contextually rich problems pertaining to force, Newton's second law of motion, and linear kinematics.
Science4Fun
Science4 Fun: Gravity
Peruse this resource to learn about gravity, its importance, the Universal Law of Gravitation, the difference between mass and weight, and more fun facts.