In Pathology of Blunt Force Traumatic Injury, forensic pathology expert witness William A. Cox, MD (www.forensicjournals.com), writes:
In this article we will review the gross and microscopic appearance of Blunt Force Traumatic Injuries and the mechanisms which causes them. The Blunt Force Traumatic Injuries covered are abrasions, contusions, lacerations, fractures, compression and hemorrhage.
General Concepts The appearance of blunt force traumatic injuries is determined by the physical characteristics of a moving object, which has an impact on the victim or the nature of the surface, which the moving victim strikes. Whether an impact results in injury is
depended upon its components, one of which is the kinetic energy displaced by the object in motion. This kinetic energy is expressed by the formula MV²/2g, in which M is the weight of the object in pounds, the weight of the object in pounds, V is the velocity in feet per second and g is the acceleration of gravity which is 32 ft. per second. Thus, the ability of an object to induce injury is dependent on its weight and velocity.
Read more: http://forensicmd.files.wordpress.com/2011/05/blunt-force-traumatic-injuries.pdf.