The tongue weight is the amount of downward weight applied to the ball on your trailer hitch. This weight can vary, but is usually in the area of 10% to 15% of the GVWR of your trailer -- the ideal percentage being around 12%. The more tongue weight you have, the less available payload you have in your tow vehicle. The less tongue weight you have, the more susceptible you are to sway. Your tongue weight will increase with anything you load forward of the fulcrum point (axles) of your trailer. The tongue weight will decrease with anything you load behind the fulcrum. Tongue weight is dynamic and is something you need to pay attention to when deciding how you are going to load your trailer.
Bruce