What are Business Objects and what is Business Logic?

This is easy

Every entity in the system, representing the human-world object which the system is expected to interact with is a business object.

The human-world logic in the system around manipulating business objects is a business logic.

This is opposed to the objects and logic being part of the implementation details.

For example in the multi-tier trading system order/trade will be business objects, but heartbeat will be implementation detail.

The logic of encoding order/trade objects for streaming will be implementation detail, while the logic of changing the order state to 'completed' once trade arrives is a business logic.

Well, a Business Object is generally considered to be a class that represents an Entity, e.g. a Book or a Store. Such a class has certain properties like price, colour, width, isbn number etc. In Java or .NET, it consists of so-called setters and getters, i.e. methods that set or get those properies.

The Business Logic on the other hand is that part of a program that works with that properties, i.e. how is this book sold. The business logic layer uses the business objects in order to access the database.