Heat, gravity, wind and running water are all causes of erosion. Each process works differently and is affected by circumstances, such as location and climate.
Gravity plays a huge effect on erosion in the form of mass movement. During mass movement, rocks are pulled from a higher elevation to a lower one in which they are then subject to the effects of other weathering agents. Mass movement happens at varying rates and, in cases such as landslides, it can occur very quickly.
Heat causes rocks to weather through rapid temperature change. When a rock's temperature rises suddenly, it increases in size. As the rock's temperature decreases, pieces of it begin breaking off. This process of weathering through heat is known as exfoliation.
Wind and running water are constant causes of erosion that occur over extended periods of time. Wind erosion works by moving broken and loose materials away from rocks. Wind also takes these materials and crashes them against other surfaces, which wears them down. Running water both relocates and breaks down rock as it moves. Running water erosion can be a slow process, such as waves breaking up materials against the shoreline, or something more severe and sudden, such as a flood.