This activity is designed to teach students with little or no experience with vectors, free-body diagrams, or the like to apply vectors to slope stability problems. Students first learn the basic properties of vectors, vector addition, resolving forces, etc. They then apply these techniques to establish in a simplified way how geologists can determine if a slope is stable, how much loading a slope can withstand before it becomes unstable, and other principles of slope stability determination. Learning goals, context for use, teaching tips, materials, assessment tips and related resources are provided.