In physics, when is mechanical work done on an object?

In physics, work is done when a force causes an object to move in the direction of that force; work equals force multiplied by the distance moved in the force's direction (W = F × d). If you push on a wall and it doesn't move, you exert force but do no mechanical work because there is no displacement. Lifting a box, pushing a cart, or pulling a rope all involve work because the object moves in the direction of the applied force. Understanding that work requires both a force and movement in that force's direction is a key work-and-energy concept.