The combat controller training program is as follows: Combat Control Screening Course, Lackland Air Force Base, Texas This 10-day screening course focuses on physical fitness with classes in sports physiology, nutrition, basic exercises, CCT history and fundamentals. Combat Control Operator Course, Keesler AFB, Miss.
Static or dynamic friction always act in a direction opposite to the impressed force. The dynamic friction does not need in any force. It is realy directed in opposit to the velosity. And the static friction can never be without the shearing force and it is always directed in opposit to it. However, you are right - dynamic friction forces can or slow down the movement of the body or accelerate it.
Sliding friction is stronger when an object is stationary (this is called static friction) than when the object is in motion (this is called kinetic friction). When trying to move a box, it is often harder to get the box moving than it is to keep the box in motion.