Question

"Work done by external agent is negative of the work done by the conservative force." This means magnitude of work done by external agent is equal to the work done by the conservative force. This is true for an object(say a pen) in our hand and we are moving it in the air(against gravity). Now my question is that if the magnitude of both the forces is equal how can the object(pen) move? It should remain stationary. If it is moving this implies that the magnitude of the external force is greater. Please explain this to me.