Final answer:
Mechanical weathering from the exhumation of a rock body mainly occurs due to pressure release, causing the rock to expand and fracture, and is influenced by exposure to climatic elements like air, water, and temperature fluctuations.
Step-by-step explanation:
The exhumation of a rock body leads to mechanical weathering primarily because the removal of overlying rock reduces pressure on the rock body, causing it to expand and fracture. This process is known as pressure release or unloading and can result in the formation of sheeting or exfoliation, where sheets of rock peel away from the rock below. Mechanical weathering also occurs when a rock body is exposed to air, causing it to dry and potentially fracture, and when temperature changes, such as those from the sunlight, cause the rock to expand and contract, leading to fracturing. However, the idea that gravitational attraction from the sun and moon would cause significant mechanical weathering of rock bodies is not significant in this context.
Exposure to rain and wind can further contribute to mechanical weathering through processes like freeze-thaw and abrasion. Acidic rainwater can also lead to chemical weathering, altering the rock's mineral composition and making it more susceptible to breakage.
Exposure to climate factors such as temperature and moisture can greatly influence the rate and type of weathering. In particular, climates with frequent temperature fluctuations and high moisture levels are more prone to mechanical and chemical weathering processes, impacting soil formation and the physical landscape.