I have been doing mechanics in college and in the present chapter,two of the concepts that I found rather confusing are principle of transmissibility and resolution of force into couple and force. 1. In resolution of a force,acting,say at a point A on a body,suppose we have to resolve the force into a force and couple acting at another point,say O on the body,the translational force is simply transferred to the point O---how is this possible? I thought that a force acting at a point is not equivalent to the same force acting at another arbitary point---for one,the torque will be different. Besides,if a force is applied at a particular point on a body,it can only be transferred to the centre of mass...we can't simply change the location of the force to any other point. Besides,please could someone tell me intuitively what we are actually doing in resolution of a force into an equivalent force and couple? 2. In principle of transmissibility,it again says that applying a force at any point on the line of action is equivalent to the original force applied at the original point. Perhaps this is all confusing me,since till now,I thought that any force applied on a body can be considered to be acting only at the centre of mass. Thanks in advance for any help.