When number of forces act simultaneously on a particle, then the resultant of these forces will have the same effect as produced by the all the forces. This is known as the principle of ______. 

Explanation:

Physical independence of forces:

• The Physical independence principal states that the effect of a force on a body is not affected by the presence of the other forces
• So even if there are a number of forces acting on the same body, each force has it’s own influence as other forces were absent.
• In other words, when number of forces act simultaneously on a particle, then the resultant of these forces will have the same effect as produced by the all the forces

Principle of transmissibility:

• Principle of transmissibility of forces states that the conditions of equilibrium or conditions of motion of a rigid body will remain unchanged if a force acting at a give point of the rigid body is replaced by a force of the same magnitude and same direction, but acting at a different point, provided that the two forces have the same line of action.