The size of the turning effect is called a turningmoment. As Newton's first law of motion states, an object will remain at rest if the forces are balanced. When the sum of the forces add to zero, a body will remain at rest or move at a constant velocity.
Forces can cause an object to rotate and the turning effect of the force is called a moment. If a resultant force acts on an object about a fixed turning point called the pivot or fulcrum it will cause the object to rotate e.g. using a spanner, a screwdriver, opening a door hanging on hinges.