To start your loaded trolley bag, you exert more force than when it is moving. This is an example of

The observation that a loaded trolley bag requires more force to start than to maintain its motion is primarily an application of Newton’s first law of motion, also known as the Law of Inertia. This law states that an object at rest tends to stay at rest unless acted upon by an external force. This resistance to change in state is called inertia, and objects with more mass (like a loaded trolley) possess greater inertia. To initiate motion, one must overcome the 'inertia of rest' and the static friction between the surfaces. Static friction is generally greater than kinetic friction, which acts once the object is already moving. Therefore, while Newton's second law relates force to acceleration, the specific phenomenon of needing extra effort to break a state of rest is the classic definition of inertia described by the first law.