Final answer:
John's father is introducing a user fee by charging John for using the family mower, which is a payment for the specific use of a service or facility.
Step-by-step explanation:
When John's father decides to charge John for using the family mower, the action he is taking is commonly known as introducing a user fee. A user fee is a charge for the use of a service or facility. Unlike a tax, which is a compulsory contribution to state revenue, a user fee is a charge applied directly to the user of a particular service for the specific purpose of funding that service. This is more like a payment for services rendered than a tax or a fine, which are imposed regardless of usage. In this context, the mower represents a service or amenity provided by John's father, and requiring a payment for its usage corresponds to the concept of a user fee. Gift-giving would be when something is given without expectation of payment, imposition of a tax is a government's levy on individuals or entities, and implementing a fine is a penalty for wrongdoing, none of which apply to this situation.